Patterned thin film dielectric stack formation

ABSTRACT

A method of producing a patterned inorganic thin film dielectric stack includes providing a substrate. A first patterned deposition inhibiting material layer is provided on the substrate. A first inorganic thin film dielectric material layer is selectively deposited on a region of the substrate where the first deposition inhibiting material layer is not present using an atomic layer deposition process. The first deposition inhibiting and first inorganic thin film dielectric material layers are simultaneously treated after deposition of the first inorganic thin film dielectric material layer. A second patterned deposition inhibiting material layer is provided on the substrate. A second inorganic thin film dielectric material layer is selectively deposited on a region of the substrate where the second deposition inhibiting material layer is not present using an atomic layer deposition process. The first and second inorganic thin film dielectric material layers form a patterned inorganic thin film dielectric stack.

Reference is made to commonly-assigned, U.S. patent applications Ser.No. 13/600,264 , entitled “THIN FILM DIELECTRIC LAYER FORMATION”, andSer. No. 13/600,287, entitled “PATTERNED THIN FILM DIELECTRIC LAYERFORMATION”, all filed concurrently herewith.

FIELD OF THE INVENTION

This invention relates generally to patterned thin film fabrication andelectronic and optoelectronic devices including patterned thin films. Inparticular, this invention relates to selective area deposition ofmaterials including, for example, metal-oxides, and devices including,for example, thin film transistors and photovoltaics, produced usingthis fabrication technique.

BACKGROUND OF THE INVENTION

Modern-day electronics require multiple patterned layers of electricallyor optically active materials, sometimes over a relatively largesubstrate. Electronics such as radio frequency identification (RFID)tags, photovoltaics, optical and chemical sensors all require some levelof patterning in their electronic circuitry. Flat panel displays, suchas liquid crystal displays or electroluminescent displays (for example,OLED), rely upon accurately patterned sequential layers to form thinfilm components of the backplane. These components include capacitors,transistors, and power buses. The industry is continually looking fornew methods of materials deposition and layer patterning for bothperformance gains and cost reductions. Thin film transistors (TFTs) maybe viewed as representative of the electronic and manufacturing issuesfor many thin film components. TFTs are widely used as switchingelements in electronics, for example, in active-matrix liquid-crystaldisplays, smart cards, and a variety of other electronic devices andcomponents thereof.

There is a growing interest in depositing thin film semiconductors onplastic or flexible substrates, particularly because these supports aremore mechanically robust, lighter weight, and allow more economicmanufacturing, for example, by allowing roll-to-roll processing.Plastics, however, typically limit device processing to below 200° C.There are other many issues associated with plastic supports when usingtraditional photolithography during conventional manufacturing, makingit difficult to perform alignments of transistor components acrosstypical substrate widths up to one meter or more. Traditionalphotolithographic processes and equipment may be seriously impacted bythe substrate's maximum process temperature, solvent resistance,dimensional stability, water, and solvent swelling, all key parametersin which plastic supports are typically inferior to glass.

The discovery of practical inorganic semiconductors as a replacement forcurrent silicon-based technologies has also been the subject ofconsiderable research efforts. For example, metal oxide semiconductorsare known that constitute zinc oxide, indium oxide, gallium indium zincoxide, tin oxide, or cadmium oxide deposited with or without additionaldoping elements including metals such as aluminum. Such semiconductormaterials, which are transparent, can have an additional advantage forcertain applications, as discussed below. Additionally, metal oxidedielectrics such as alumina (Al₂O₃) and TiO₂ are useful in practicalelectronics applications as well as optical applications such asinterference filters. Dielectric materials that are easily processableand patternable are also important to the success of low cost andflexible electronic devices. In addition, metal oxide materials canserve as barrier or encapsulation elements in various electronicdevices. These materials also require patterning so that a connectioncan be made to the encapsulated devices.

Atomic layer deposition (ALD) can be used as a fabrication step forforming a number of types of thin-film electronic devices, includingsemiconductor devices and supporting electronic components such asresistors and capacitors, insulators, bus lines, and other conductivestructures. ALD is particularly suited for forming thin layers of metaloxides in the components of electronic devices. General classes offunctional materials that can be deposited with ALD include conductors,dielectrics or insulators, and semiconductors. Examples of usefulsemiconducting materials are compound semiconductors such as galliumarsenide, gallium nitride, cadmium sulfide, zinc oxide, and zincsulfide.

A number of device structures can be made with the functional layersdescribed above. A capacitor results from placing a dielectric betweentwo conductors. A diode results from placing two semiconductors ofcomplementary carrier type between two conducting electrodes. There mayalso be disposed between the semiconductors of complementary carriertype a semiconductor region that is intrinsic, indicating that thatregion has low numbers of free charge carriers. A diode may also beconstructed by placing a single semiconductor between two conductors,where one of the conductor/semiconductors interfaces produces a Schottkybarrier that impedes current flow strongly in one direction. Atransistor results from placing upon a conductor (the gate) aninsulating layer followed by a semiconducting layer. If two or moreadditional conductor electrodes (source and drain) are placed spacedapart in contact with the top semiconductor layer, a transistor can beformed. Any of the above devices can be created in variousconfigurations as long as the critical interfaces are created.

Advantageously, ALD steps are self-terminating and can deposit preciselyone atomic layer when conducted up to or beyond self-terminationexposure times. An atomic layer typically ranges from about 0.1 to about0.5 molecular monolayers, with typical dimensions on the order of nomore than a few Angstroms. In ALD, deposition of an atomic layer is theoutcome of a chemical reaction between a reactive molecular precursorand the substrate. In each separate ALD reaction-deposition step, thenet reaction deposits the desired atomic layer and substantiallyeliminates “extra” atoms originally included in the molecular precursor.In its most pure form, ALD involves the adsorption and reaction of eachof the precursors in the complete absence of the other precursor orprecursors of the reaction. In practice, as in any process, it isdifficult to avoid some direct reaction of the different precursorsleading to a small amount of chemical vapor deposition reaction. Thegoal of any process claiming to perform ALD is to obtain deviceperformance and attributes commensurate with an ALD process whilerecognizing that a small amount of CVD reaction can be tolerated.

In ALD processes, typically two molecular precursors are introduced intothe ALD reactor in separate stages. U.S. Patent Application Publication2005/0084610 (Selitser) discloses an atmospheric pressure atomic layerchemical vapor deposition process that involve separate chambers foreach stage of the process and a series of separated injectors are spacedaround a rotating circular substrate holder track. A spatially dependentALD process can be accomplished using one or more of the systems ormethods described in more detail in WO 2008/082472 (Cok), U.S. PatentApplication Publications 2008/0166880 (Levy), 2009/0130858 (Levy),2009/0078204 (Kerr et al.), 2009/0051749 (Baker), 2009/0081366 (Kerr etal.), and U.S. Pat. No. 7,413,982 (Levy), U.S. Pat. No. 7,456,429(Levy), and U.S. Pat. No. 7,789,961 (Nelson et al.), U.S. Pat. No.7,572,686 (Levy et al.), all of which are hereby incorporated byreference in their entirety.

There is growing interest in combining ALD with a technology known asselective area deposition (SAD). As the name implies, selective areadeposition involves treating portion(s) of a substrate such that amaterial is deposited only in those areas that are desired, or selected.Sinha et al. (J. Vac. Sci. Technol. B 24 6 2523-2532 (2006)), haveremarked that selective area ALD requires that designated areas of asurface be masked or “protected” to prevent ALD reactions in thoseselected areas, thus ensuring that the ALD film nucleates and grows onlyon the desired unmasked regions. It is also possible to have SADprocesses where the selected areas of the surface area are “activated”or surface modified in such a way that the film is deposited only on theactivated areas. There are many potential advantages to selective areadeposition techniques, such as eliminating an etch process for filmpatterning, reduction in the number of cleaning steps required, andpatterning of materials which are difficult to etch. One approach tocombining patterning and depositing the semiconductor is shown in U.S.Pat. No. 7,160,819 entitled “METHOD TO PERFORM SELECTIVE ATOMIC LAYERDEPOSITION OF ZINC OXIDE” by Conley et al. Conley et al. discussmaterials for use in patterning Zinc Oxide on silicon wafers. Noinformation is provided, however, on the use of other substrates, or theresults for other metal oxides.

SAD work to date has focused on the problem of patterning a singlematerial during deposition. There persists a problem of combiningmultiple SAD steps to form working devices. Processes for buildingcomplete devices need to be able to control the properties the criticalinterfaces, particularly in field effect devices like TFTs.

Although there are many approaches to forming high quality dielectriclayer they typically fall into one of two categories: a single thicklayer of a single material or multiple layers of differing materialtypes. In the case of devices which use a single layer dielectric, largethicknesses are required for defect mitigation to ensure high deviceyield. This required layer thickness typically requires long processingtimes and limits the functionality of field effect devices. Devicesformed with a multilayer stack of materials use thin layers of materialsdeposited using the same equipment requiring complex equipment designand multiple precursors. Accordingly, there still remains a need for ahigh quality dielectric that can be formed from a single material forease of processing and single precursors, and that doesn't require athick layer for performance and device yield. Additionally, a method isneeded to simply pattern this layer for easy device integration.

SUMMARY OF THE INVENTION

According to an aspect of the invention, a method of producing apatterned inorganic thin film dielectric stack includes providing asubstrate. A first patterned deposition inhibiting material layer isprovided on the substrate. A first inorganic thin film dielectricmaterial layer is selectively deposited on a region of the substratewhere the first deposition inhibiting material layer is not presentusing an atomic layer deposition process. The first depositioninhibiting material layer and the first inorganic thin film dielectricmaterial layer are simultaneously treated after the deposition of thefirst inorganic thin film dielectric material layer. A second patterneddeposition inhibiting material layer is provided on the substrate. Asecond inorganic thin film dielectric material layer is selectivelydeposited on a region of the substrate where the second depositioninhibiting material layer is not present using an atomic layerdeposition process, the first inorganic thin film dielectric materiallayer and the second inorganic thin film dielectric material layerforming a patterned inorganic thin film dielectric stack.

According to another aspect of the present invention, selective areadeposition of metal oxides or other materials is used in a process thatcombines a spatially dependent atomic layer deposition. Advantageously,the present invention is adaptable for deposition on a web or othermoving substrate including deposition on large area substrates.

BRIEF DESCRIPTION OF THE DRAWINGS

In the detailed description of the example embodiments of the inventionpresented below, reference is made to the accompanying drawings, inwhich:

FIG. 1 is a flow chart describing the steps of one embodiment of thepresent process for forming a multi-layer dielectric;

FIG. 2 is a flow chart describing the steps of one embodiment of thepresent process for forming a patterned multi-layer dielectric;

FIG. 3 is a flow chart describing the steps of another embodiment of thepresent process for forming a patterned multi-layer dielectric;

FIG. 4 is a flow chart describing the steps of one embodiment of thepresent process for forming a patterned multi-layer stack;

FIGS. 5 a through 5 g are cross-sectional side views of one embodimentof the present process of forming the patterned multi-layer dielectricstack as shown in FIG. 5 g;

FIGS. 6 a through 6 e are cross-sectional side views of one embodimentof the present process of forming the patterned multi-layer stack asshown in FIG. 6 e;

FIGS. 7 a through 7 g are cross-sectional side views of anotherembodiment of the present process of forming the patterned multi-layerdielectric stack as shown in FIG. 7 g;

FIGS. 8 a and 8 b are cross-sectional views and plan views,respectively, of one embodiment of the patterned multi-layer dielectricof the present invention;

FIGS. 9 a and 9 b are cross-sectional views and plan views,respectively, of another embodiment of the patterned multi-layerdielectric of the present invention;

FIGS. 10 a and 10 b are cross-sectional views and plan views,respectively, of another embodiment of the patterned multi-layerdielectric of the present invention;

FIGS. 11 a and 11 b are cross-sectional views and plan views,respectively, of one embodiment of a thin film transistor of the presentinvention;

FIGS. 12 a and 12 b are cross-sectional views and plan views,respectively, of another embodiment of a thin film transistor of thepresent invention;

FIGS. 13 a and 13 b are cross-sectional views and plan views,respectively, of another embodiment of a thin film transistor of thepresent invention;

FIGS. 14 a and 14 b are cross-sectional views and plan views,respectively, of another embodiment of a thin film transistor of thepresent invention;

FIGS. 15 a and 15 b through FIGS. 27 a and 27 b are cross-sectionalviews and plan views, respectively, of the process of forming oneembodiment of a thin film transistor of the present invention;

FIG. 28 is a cross-sectional side view of a deposition device, used inan exemplified process, showing the arrangement of gaseous materialsprovided to a substrate that is subject to the thin film depositionprocess of the Examples;

FIG. 29 is a cross-sectional side view of a deposition device, used inthe process of FIG. 28, showing the arrangement of gaseous materialsprovided to a substrate that is subject to the thin film depositionprocess of the Examples; and

FIG. 30 is a plot comparing the intensity signal of two species in asingle layer dielectric film and a multilayer dielectric film.

DETAILED DESCRIPTION OF THE INVENTION

For the description that follows, the term “gas” or “gaseous material”is used in a broad sense to encompass any of a range of vaporized orgaseous elements, compounds, or materials. Other terms used herein, suchas: reactant, precursor, vacuum, and inert gas, for example, all havetheir conventional meanings as would be well understood by those skilledin the materials deposition art. The figures provided are not drawn toscale but are intended to show overall function and the structuralarrangement of some embodiments of the present invention.

The embodiments of the present invention all relate to thin filminorganic materials and devices that contain them. Example embodimentsof the present invention use selective area deposition (SAD) incombination with atomic layer deposition (ALD). SAD employs a patternedmaterial referred to as a “deposition inhibitor material”, “depositioninhibiting material”, or simply an “inhibitor” that inhibits the growthof a thin film material on the substrate when the substrate is subjectedto an atomic layer deposition. By inhibiting the growth where thedeposition material is present, the deposition only deposits in regions(selective areas) of the substrate where the inhibitor is not present.The phrase “deposition inhibitor material” and its equivalents referherein to any material on the substrate that inhibits the deposition ofmaterial during atomic layer deposition (ALD). The “deposition inhibitormaterial” includes the material applied to the substrate as well as thematerial resulting from any optionally subsequent crosslinking or otherreaction that modifies the material that can occur prior to depositingan inorganic thin film on the substrate by atomic layer deposition. Apolymeric deposition inhibitor material can be crosslinked afterapplying the polymer onto the substrate, before or during the patteringstep.

The deposition inhibitor material can be a compound or polymer that,after being applied, is subsequently polymerized, crosslinked, orpolymerized and crosslinked. The deposition inhibitor material can be acompound or polymer that forms a self-assembled monolayer on thesubstrate. Polymers are preferably addition polymers such as, forexample, a poly(perfluoroalkyl methacrylate); poly(perfluoroalkylmethacrylate); poly(methyl methacrylate); poly(cyclohexyl methacrylate);poly(benzyl methacrylate); poly(iso-butylene);poly(9,9-dioctylfluorenyl-2,7-diyl); polystyrene; poly(vinyl alcohol);poly(methyl methacrylate); poly(hexafluorobutyl methacrylate), andcopolymers thereof, wherein the alkyl has one to six carbon atoms.

Crosslinking can be used to insolubilize a polymeric depositioninhibitor material after application onto the surface of the substrate.The crosslinking can occur prior to patterning or can occur duringpatterning in order to contribute to the patterning step, for example,by employing crosslinking initiated by, and patterned by, actinicradiation, followed by removal of non-crosslinked polymer, for example,by solvent.

The deposition inhibitor material can be an organosiloxane polymer.Organosiloxane polymers are defined to include polymers, prepolymers, ormacromonomers having at least 20 siloxane repeat units. Particularlypreferred are deposition inhibitor materials that, after applicationonto the substrate, and any crosslinking or intermolecular reaction, areinsoluble. Such organosiloxane polymers include random or block orcrosslinked polymers or combinations thereof. Optionally, functionalgroups can be present on the organosiloxane polymer such as terminalgroups (also referred to as end caps). Crosslinking groups or functionalgroups or combinations of crosslinking groups and functional groups canalso be present, for example, located on a side chain off a siloxanebackbone. Examples of organosiloxane polymers includepoly(alkylsiloxane), poly(arylsiloxane), poly(alkylarylsiloxane), andpoly(alkyl(aryl)siloxane), each optionally having functional groups.

Functionalized poly(siloxanes) include epoxy-functionalized,carboxyl-functionalized, polyether-functionalized,phenol-functionalized, amino-functionalized, alkoxy-functionalized,methacryl-functionalized, carbinol-functionalized,hydroxy-functionalized, vinyl-functionalized, acrylic-functionalized,silane-functionalized, trifluoro-functionalized, ormercapto-functionalized poly(organosiloxanes). Block copolymers can alsobe employed if containing substantial siloxane repeat units. Suchpolymers can be prepared as described in numerous patents andpublications or are commercially available from, for example, GeneralElectric Company, Schenectady, N.Y.; Dow Corning, Midland, Mich.; orPetrarch Systems, Bristol, Pa.

The deposition inhibiting material layer includes one of a selfassembled monolayer, a polymer, and a water soluble polymer. The selfassembled monolayer can be performed by exposing the substrate to avapor, a liquid, or a liquid solution of a precursor material. Precursormaterials include silanes, phosphonates, thiols, alcohols, amines, orammonium salts. The polymer can be soluble in any convenient solvent andcan have any useful molecular weight, preferably in the range of 2,000to 2,000,000. It can include a single functional group, or can include aplurality of functional groups. In the case of a plurality, the polymercan be a random, periodic, or block polymer. For polymers with chiralcenters the polymer can be isotactic, syndiotactic, or atactic. Thepolymer can have side chains and can be a graft copolymer. The polymercan be linear or branched. The polymer can have low numbers of free acidgroups. Preferred polymers that a soluble in non polar solvents arepoly(methylmethcrylate), silicone polymers includingpoly(dimethylsiloxane), poly(carbonates), poly(sulfones), andpoly(esters). Polymers with chemical modification are preferred,including polymers modified with fluorine or fluorine containingcompounds. Polymers soluble in polar solvents such as water, alcohols,or ketones are particularly preferred. Polymers can include amidegroups, such as poly(amide), poly(vinylpyrollidone), andpoly(2-ethyl-oxazoline). Polymers can include ether linkages, such aspoly(ethylene glycol). Polymers can include alcohol functionalities,such as poly(vinyl alcohol). Polymers can include neutralized acidgroups such as sodium poly(styrene sulfonate) and the sodium salt ofpoly(acrylic acid).

In some embodiments, the deposition inhibitor material is chosenspecifically for the material to be deposited. The deposition inhibitormaterial has a given inhibition power. The inhibition power is definedas the layer thickness at or below which the deposition inhibitormaterial is effective. Preferably, the deposition inhibitor material,during use, exhibits an inhibition power of at least 50 Å, morepreferably at least 100 Å, most preferably at least 300 Å. Thedeposition of the deposition inhibitor material can be in a patternedmanner, such as using inkjet, flexography, gravure printing,micro-contact printing, offset lithography, patch coating, screenprinting, or transfer from a donor sheet. In alternative embodiments, auniform layer of the deposition inhibitor material can be deposited andthen patterned form a patterned layer of the deposition inhibitormaterial. Preprocessing treatments for patterning the inhibitor includepatterning of substrate prior to inhibitor application to modify thehydrophobilicity, electric charge, absorption, or roughness of thesubstrate. Post processing treatments include light exposure, lightexposure and subsequent liquid based development, and ablation.

Providing the patterned deposition inhibiting material layer on thesubstrate includes using at least one of an inkjet printing process, aflexographic printing process, a gravure printing process, and aphotolithographic printing process. The active inhibiting material canbe suspended or dissolved in a solvent or vehicle. The material caninclude surfactants, stabilizers, or viscosity modifiers. The printedmaterial can be dried using natural convection, forced convection, orradiant heat. The material can be treated to change its morphology orchemical composition. A preferred chemical composition change is tocrosslink the material. The change in morphology or chemical compositioncan be accomplished by exposure to a vapor phase or liquid phasereactant, or treatment with heat or light. Preferred processes includethe crosslinking of material with UV light.

The process of making the thin films of the present invention can becarried out below a maximum support temperature of about 300° C., morepreferably below 250° C., or even at temperatures around roomtemperature (about 25° C. to 70° C.). These temperatures are well belowtraditional integrated circuit and semiconductor processingtemperatures, which enable the use of any of a variety of relativelyinexpensive supports, such as flexible polymeric supports. Thus, theinvention enables production of relatively inexpensive circuitscontaining thin film transistors with significantly improvedperformance.

The substrates used in the present invention can be any material thatacts as a mechanical support for the subsequently coated layers. Thesubstrate can include a rigid material such as glass, silicon, ormetals. Particularly useful metals are stainless steel, steel, aluminum,nickel, and molybdenum. The substrate can also include a flexiblematerial such as a polymer film or paper such as Teslin. Usefulsubstrate materials include organic or inorganic materials. For example,the substrate can include inorganic glasses, ceramic foils, polymericmaterials, filled polymeric materials, coated metallic foils, acrylics,epoxies, polyamides, polycarbonates, polyimides, polyketones,poly(oxy-1,4-phenyleneoxy-1,4-phenylenecarbonyl-1,4-phenylene)(sometimes referred to as poly(ether ether ketone) or PEEK),polynorbornenes, polyphenyleneoxides, poly(ethylenenaphthalenedicarboxylate) (PEN), poly(ethylene terephthalate) (PET),poly(ether sulfone) (PES), poly(phenylene sulfide) (PPS), andfiber-reinforced plastics (FRP). The thickness of substrate 110 canvary, typically from about 100 μm to about 1 cm.

A flexible support or substrate can be used in the present invention.Using a flexible substrate allows for roll processing, which can becontinuous, providing economy of scale and economy of manufacturing overflat or rigid supports. The flexible support chosen is preferablycapable of wrapping around the circumference of a cylinder of less thanabout 50 cm in diameter, more preferably 25 cm in diameter, and mostpreferably 10 cm in diameter, without distorting or breaking, using lowforce as by unaided hands. The preferred flexible support can be rolledupon itself. Additional examples of flexible substrates include thinmetal foils such as stainless steel provided the foils are coated withan electrically insulating material layer to electrically isolate anyelectric components such as thin film transistors. Nominally rigidmaterials that are flexible due to their thinness can also be used.These include glass at thicknesses below 200 μm and metals atthicknesses below 500 μm.

In some example embodiments, the substrate can include a temporarysupport or support material layer, for example, when additionalstructural support is desired for a temporary purpose, e.g.,manufacturing, transport, testing, or storage. In these exampleembodiments, substrate can be detachably adhered or mechanically affixedto the temporary support. For example, a flexible polymeric support canbe temporarily adhered to a rigid glass support to provide addedstructural rigidity during the transistor manufacturing process. Theglass support can be removed from the flexible polymeric support aftercompletion of the manufacturing process.

The substrate can be bare indicating that it contains no substantialmaterials on its surface other the material from which it is composed.The substrate can include various layers on the surface. These layersinclude subbing layers, adhesion layers, release layers, wetting layers,hydrophilic layers, and hydrophobic layers. The substrate surface can betreated in order to promote various properties. These treatments includeplasma treatments, corona discharge treatments, and chemical treatments.

The substrate can also include on its surface patterned materials. Thesepatterns can include patterns that modulate light transmission orelectrical conductivity within or on the substrate. The patterns caninclude complete devices, circuits, or active elements existing on thesubstrate. The patterns can include portions of devices, circuits, oractive elements awaiting subsequent processing steps for completion.

Atomic Layer Deposition (ALD) is a process which is used to producecoatings with thicknesses that can be considered consistent, uniform, oreven exact. ALD produces coatings that can be considered conformal oreven highly conformal material layers. Generally described, an ALDprocess accomplishes substrate coating by alternating between two ormore reactive materials commonly referred to as precursors, in a vacuumchamber. A first precursor is applied to react with the substrate. Theexcess of the first precursor is removed is removed from the vacuumchamber. A second precursor is then applied to react with the firstprecursor on the substrate. The excess of the second precursor isremoved from the vacuum chamber and the process is repeated.

Recently, a new ALD process has been developed which negates the needfor a vacuum chamber. This process, commonly referred to as S-ALD, isdescribed in at least one of U.S. Pat. Nos. 7,413,982, 7,456,429,7,789,961, and US 2009/0130858, the disclosures of which areincorporated by reference herein. S-ALD produces coatings withthicknesses that can be considered consistent, uniform, or even exact.S-ALD produces coatings that can be considered conformal or even highlyconformal material layers. S-ALD is also compatible with a lowtemperature coating environment. Additionally, S-ALD is compatible withweb coating, making it attractive for large scale production operations.Even though some web coating operations can experience alignment issues,for example, web tracking or stretching issues, the architecture of thepresent invention reduces reliance on high resolution or very finealignment features during the manufacturing process. As such, S-ALD iswell suited for manufacturing the present invention.

The preferred process of the present invention employs a continuousspatially dependent ALD (as opposed to pulsed or time dependent ALD)gaseous material distribution. The process of the present inventionallows operation at atmospheric or near-atmospheric pressures and iscapable of operating in an unsealed or open-air environment. The processof the present invention is adapted such that material is deposited onlyin selected areas of a substrate.

Atomic layer deposition can be used in the present invention to deposita variety of inorganic thin films that are metals or that comprise ametal-containing compound. Such metal-containing compounds include, forexample (with respect to the Periodic Table) a Group V or Group VIanion. Such metal-containing compounds can, for example, include oxides,nitrides, sulfides or phosphides of zinc, aluminum, titanium, hafnium,zirconium or indium, or combinations thereof.

Oxides that can be made using the process of the present inventioninclude, but are not limited to: zinc oxide (ZnO), aluminum oxide(Al₂O₃), hafnium oxide, zirconium oxide, indium oxide, tin oxide, andthe like. Mixed structure oxides that can be made using the process ofthe present invention can include, for example, InZnO. Doped materialsthat can be made using the process of the present invention can include,for example, ZnO:Al, Mg_(x)Zn_(1-x)O, and LiZnO.

A dielectric material is any material that is a poor conductor ofelectricity. Such materials typically exhibit a bulk resistivity greaterthan 10¹⁰ Ω-cm. Examples of dielectrics are SiO2, HfO, ZrO, SiNx, andAl₂O₃. A semiconductor is a material in which electrical charges canmove but in which the concentration of electrical charges can besubstantially modulated by external factors such as electrical fields,temperature, or injection of electrical charges from a neighboringmaterial. Examples of semiconductors include silicon, germanium, andgallium arsenide. Particularly preferred semiconductors are zinc oxide,indium zinc oxide, and gallium indium zinc oxide. The semiconductors canbe doped to render them n-type or p-type, or to modulated the number ofcharge carriers present.

Metals that can be made using the process of the present inventioninclude, but are not limited to: copper, tungsten, aluminum, nickel,ruthenium, and rhodium. It should be apparent to the skilled artisanthat alloys of two, three, or more metals can be deposited, compoundscan be deposited with two, three, or more constituents, and such thingsas graded films and nano-laminates can be produced as well.

These variations are simply variants using particular embodiments of theinvention in alternating cycles. There are many other variations withinthe scope of the invention, so the invention is limited only by theclaims that follow.

For various volatile zinc-containing precursors, precursor combinations,and reactants useful in ALD thin film processes, reference is made tothe Handbook of Thin Film Process Technology, Vol. 1, edited by Glockerand Shah, Institute of Physics (IOP) Publishing, Philadelphia 1995,pages B1.5:1 to B1.5:16, hereby incorporated by reference, and Handbookof Thin Film Materials, edited by Nalwa, Vol. 1, pages 103 to 159,hereby incorporated by reference, including Table V 1.5.1 of the formerreference.

Although oxide substrates provide groups for ALD deposition, plasticsubstrates can be used by suitable surface treatment.

In a preferred embodiment, ALD can be performed at or near atmosphericpressure and over a broad range of ambient and substrate temperatures,preferably at a temperature of under 300° C. Preferably, a relativelyclean environment is needed to minimize the likelihood of contamination;however, full “clean room” conditions or an inert gas-filled enclosurewould not be required for obtaining good performance when usingpreferred embodiments of the process of the present invention.

Optionally, the present process can be accomplished using a new ALDprocess which negates the need for a vacuum chamber. This process,commonly referred to as S-ALD, is described in at least one of commonlyassigned U.S. Pat. Nos. 7,413,982; 7,456,429; 7,789,961; and US PatentApplication Publication No. US 2009/0130858. All of the above-identifiedpatents and patent applications are incorporated by reference herein intheir entirety.

Two suitable approaches to combining patterning and depositing thesemiconductor are described in US Patent Application Publication No.2009/0081827 A1, published to Yang et al., on Mar. 26, 2009, thedisclosure of which is hereby incorporated by reference in its entirety;and U.S. Pat. No. 8,017,183 B2, issued to Yang et al., on Sep. 13, 2011,the disclosure of which is hereby incorporated by reference in itsentirety. Given that the preferred subsequent layers are deposited andconformally coated by atomic layer deposition (ALD), preferreddeposition inhibitor materials are described in U.S. Pat. No. 7,998,878B2, issued to Levy et al., on Aug. 16, 2011, the disclosure of which ishereby incorporated by reference in its entirety. In addition,deposition inhibitor materials are chosen to be compatible with printingon large flexible substrates in a low cost manner.

In some embodiments of the present invention, treating the surface priorto depositing a layer by ALD is an important process step. For thedescription that follows, the term “treating” can be taken to meansubjecting the substrate to a different environmental condition thanthat experienced during the ALD deposition. Treating can occur eitherwithin the ALD system, or preferably, the substrate is removed from thesystem and treated off-line. Surface treatments include dry cleaning,such as a UV-ozone treatment, or a gas plasma, for example andpreferably an oxygen plasma. Other treatments include wet clean steps,hold at ambient conditions, wet or dry etching the surface of a materiallayer, and other processes. An example cleaning process includes aliquid process using a solvent or a detergent. The liquid process canutilize a mechanical action such as brushing or wiping or pressure jets.The cleaning process can also be a vapor process. These processesinclude exposing the substrate to a vapor reactant that causes cleaning.The vapor exposure can include forms of energy to promote the process.These include light exposure, arcs, or plasmas. Particularly desiredlight exposures include UV exposure, especially in the presence ofoxygen to produce ozone (UV-ozone). Plasmas include plasmas of variousspecies including oxygen, chlorine, and fluorine. Plasmas created withthese materials or with precursors that produce these materials areincluded in the present invention.

Turning now to the figures, FIG. 1 is a diagrammatic step diagram forone embodiment of a process of the present invention for making aquality thin film inorganic dielectric using atomic layer deposition(ALD). As shown in Step 1, a substrate is supplied into the system. Thesubstrate can be any substrate as discussed that is suitable for use inthe ALD system. Next, Step 20 deposits the desired first thin filmdielectric material by an ALD process. Generically this deposition canbe using any ALD system, preferably a spatial ALD system. After thefirst thin film dielectric material is deposited in Step 20, the surfaceof the first thin film dielectric material layer is treated in Step 30.Treating Step 30 requires that the substrate with the first thin filmdielectric material be subjected to a different environmental conditionthan that experienced during the deposition of the first thin filmdielectric. Treating can occur either within the ALD system, orpreferably, the substrate is removed from the system and treatedoff-line. Surface treatments include dry cleaning, such as a UV-ozonetreatment, gas plasma, preferably an oxygen plasma. Other treatmentsinclude wet clean steps, hold at ambient conditions, wet or dry etchingthe surface of the first thin film dielectric material layer, and otherprocesses.

After treating the surface of the first thin film dielectric materiallayer, a second thin film dielectric material is deposited by ALD inStep 50. The second thin film dielectric material can be the differentfrom that of the first thin film dielectric material, or preferably thesame as that of the first thin film dielectric material. The layerthickness of the first and second thin film dielectric material can bethe same or different. At least one of the first inorganic thin filmdielectric material layer and the second inorganic thin film dielectricmaterial layer can include Al₂O₃, SiO₂, HfO, ZrO, TiO₂, Ta₂O₅,Si_(x)N_(y) or any other thin film inorganic material that can bedeposited by ALD. Preferably both thin film dielectric material layersare Al₂O₃.

The process flow described by FIG. 1 is effective in making a qualitydielectric layer that can be subsequently patterned. Turning now to FIG.2, a diagrammatic Step diagram is shown for one embodiment of a processof the present invention for making a patterned thin film inorganicdielectric using a combination of selected area deposition (SAD) andALD. As shown in Step 1, a substrate is supplied into the system. InStep 10 a deposition inhibitor material is deposited. The depositioninhibitor material can generically be any material that causes thematerial deposition to be inhibited and should be understood from theprevious descriptions. In one embodiment, the deposition inhibitormaterial is chosen specifically for the material to be deposited. Inother embodiments, the deposition inhibitor material has a giveninhibition power. The inhibition power is defined as the layer thicknessat or below which the deposition inhibitor material is effective. Thedeposition of the deposition inhibitor material in Step 10 can be in apatterned manner, such as using inkjet, flexography, gravure printing,micro-contact printing, offset lithography, patch coating, screenprinting, or transfer from a donor sheet. In an alternative embodiment,Step 10 can deposit a uniform layer of the deposition inhibitor materialand Step 15 can be optionally employed to form a patterned layer of thedeposition inhibitor material.

Continuing with FIG. 2, Step 20 deposits the desired first thin filmmaterial by an Atomic Layer Deposition (ALD) process. Generically thisdeposition can be using any ALD system, preferably a spatial ALD system.The thin film material is deposited only in the areas of the substratewhere there is no deposition inhibitor material. After the first thinfilm dielectric material is deposited in Step 20, the surface of thefirst thin film dielectric material layer and the deposition inhibitorcompound are treated simultaneously in Step 25. Treating Step 25requires that the substrate with the first thin film dielectric materialand deposition inhibitor compound be subjected to a differentenvironmental condition than that experienced during the deposition ofthe first thin film dielectric material. Treating can occur eitherwithin the ALD system, or preferably, the substrate is removed from thesystem and treated off-line. Surface treatments include dry cleaning,such as a UV-ozone treatment, gas plasma, preferably an oxygen plasma.Other treatments include wet clean steps, hold at ambient conditions,and the like. Simultaneous treating Step 25 can partially or completelyremove the deposition inhibitor material. After the surface treatment, adeposition inhibitor is applied in Step 35. As in Step 10, thedeposition inhibitor material can be deposited in a patterned manner, oras a uniform layer and Step 35 can be optionally employed to form apatterned layer of the deposition inhibitor material. The pattern of thesecond patterned deposition inhibiting material can be the same as ordifferent than the pattern of the first patterned deposition inhibitingmaterial.

After providing the second patterned deposition inhibiting materiallayer on the substrate a second thin film dielectric material isdeposited by ALD in Step 50. The second thin film dielectric materialcan be the different from that of the first thin film dielectricmaterial, or preferably the same as that of the first thin filmdielectric material. The layer thickness of the first and second thinfilm dielectric material can be the same or different. After depositingthe second thin film dielectric material, the deposition inhibitormaterial can be optionally removed in Step 60.

The process flow described in FIG. 2 can be better understood throughthe descriptive process build shown in FIGS. 5 a through 5 g. In FIG. 5a, the substrate 200 is provided as in Step 1 of FIG. 2. FIG. 5 b showsthe first patterned deposition inhibiting material layer 210 on thesubstrate 200. The first pattern deposition inhibiting material layer210 contains regions 215 where the first deposition inhibiting materiallayer is not present. FIG. 5 c illustrates the patterned first inorganicthin film dielectric material 220 obtained after coating the firstpattern deposition inhibiting material layer 210 using an ALD process.Next, the patterned first inorganic thin film dielectric material 220and the first pattern deposition inhibiting material layer 210 aresimultaneously treated cleaning the surface of the patterned firstinorganic thin film dielectric material 220 and removing the firstpattern deposition inhibiting material layer 210 as shown in FIG. 5 d.Next, a second pattern deposition inhibiting material layer 230 isdeposited on the substrate. As illustrated in FIG. 5 e the firstpatterned deposition inhibiting material layer 210 and the secondpatterned deposition inhibiting material layer 230 have the samepattern, it should be understood that the first pattern 210 and thesecond pattern 230 can be different. The second patterned depositioninhibiting material layer 230 has regions 235 where the seconddeposition inhibiting material layer is not present. Regions 235 overlapwith the regions containing the first patterned first inorganic thinfilm dielectric material 220. After the second patterned depositioninhibiting material layer 230 is provide, a patterned second inorganicthin film dielectric material 240 is deposited by treating the substratesurface to an ALD coating such that the second inorganic thin filmdielectric material is only deposited in the regions 235 where thesecond deposition inhibiting material is not present. The patternedfirst inorganic thin film dielectric material 220 and patterned secondinorganic thin film dielectric material 240 in combination form thepatterned inorganic thin film dielectric stack 250 as illustrated inFIG. 5 f. If the second patterned deposition inhibiting material layer230 is optionally be removed, the patterned inorganic thin filmdielectric stack 250 as shown in FIG. 5 g is obtained.

FIGS. 7 a through 7 g describe a variation the process flow of FIG. 2.FIGS. 7 a through 7 c are equivalent to FIGS. 5 a through 5 c, andshould be understood from the previous descriptions. FIG. 7 dillustrates the resulting substrate after the patterned first inorganicthin film dielectric material 220 and the first pattern depositioninhibiting material layer 210 are simultaneously treated, cleaning thesurface of the patterned first inorganic thin film dielectric material220 and leaving a partially removed first pattern deposition inhibitingmaterial layer 225. The patterned inorganic thin film dielectric stack250 is completed using the same process steps as in FIGS. 5 e through 5g, and as such FIGS. 7 e through 7 g should be understood from theprevious descriptions.

The process flows described by FIG. 1 and FIG. 2 are effective in makinga quality unpatterned dielectric layer or fully patterned dielectriclayer respectively. Turning now to FIG. 3, a diagrammatic Step diagramis shown for one embodiment of a process of the present invention formaking a partially patterned thin film inorganic dielectric layer usinga combination of selected area deposition (SAD) and ALD. Steps 1, 20 and30 should be understood from the description of FIG. 1. After thesurface of the first thin film dielectric material layer is treated inStep 30, a deposition inhibitor is applied in Step 35 and Step 40 can beoptionally employed to form a patterned layer of the depositioninhibitor material in cases where a uniform layer of depositioninhibitor is applied in Step 35. After providing the patterneddeposition inhibiting material layer on the substrate a second thin filmdielectric material is deposited by ALD in Step 50. The second thin filmdielectric material can be the different from that of the first thinfilm dielectric material, or preferably the same as that of the firstthin film dielectric material. The layer thickness of the first andsecond thin film dielectric material can be the same or different. Afterdepositing the second thin film dielectric material, the depositioninhibitor material can be optionally removed in Step 60.

FIG. 8 a is a cross-sectional diagram of an electronic element, takenalong the line A-A′ of the plan view shown in FIG. 8 b. The processesdescribed in relation to FIGS. 1, 2, 3 5 and 7 can be used to form thiselectronic element and other electronic elements. The electronic elementshown in FIGS. 8 a and 8 b is a simple structure that should beillustrative of any element that contains two conductive layers thatneed to be kept electrically isolated. As shown in FIG. 8 b, onsubstrate 400, there is patterned first electrically conductive material410 and patterned second electrically conductive material 420 thatoverlap (in plan-view) at overlap regions 425. As shown in FIG. 8 a, thepatterned first electrically conductive material 410 can be composed ofa single material, or can include a plurality of material layers.Similarly the second conductive material 210 can be composed of a singlematerial, or a plurality of material layers. In order to keep the firstelectrically conductive material 410 and second electrically conductivematerial 420 from electrically shorting, a patterned inorganic thin filmdielectric stack 450 is disposed between them. Patterned inorganic thinfilm dielectric stack 450 is made up of patterned first inorganic thinfilm dielectric material 430 and patterned second inorganic thin filmdielectric material 440. As shown in FIG. 8 b, the patterns of the first430 and second 440 inorganic thin film dielectric materials are the samepattern and have the same material composition. Although the patternedfirst inorganic thin film dielectric material 430 and patterned secondinorganic thin film dielectric material 440 have the same materialcomposition, they do not have the same analytical signature as a singlelayer with a combined thickness of the same material. Due to thesequential processing of the two inorganic thin film dielectric materiallayers and the treatment required at the interface in order to achieve aquality patterned inorganic thin film dielectric stack 450, there is ananalytical (sometimes referred to as compositional) signature at theinterface. Typically, during the treatment of the interface, the surfaceof the substrate acquires a difference in chemical composition. This canmanifest itself as a variation in the concentration of atomic speciesformally included in the deposition materials or as the presence ofimpurity atoms or molecules. This difference in chemical composition ispresent at the interface region between the patterned first inorganicthin film dielectric material 430 and patterned second inorganic thinfilm dielectric material 440. This difference can be detected by depthprofiling the patterned inorganic thin film dielectric stack 450, wherea small change in either the relative amounts of the depositionmaterials or impurities can be detected at the interface (or contactregion) between the two layers. One analytical technique that can beused for depth profiling films is time-of-flight secondary ion massspectroscopy (ToF SIMS).

FIG. 30 shows the profiles of AlF and AlOH from a positive polarity ToFSIMS analysis of a single layer of growth and a layer containingmultiple interfaces of Al₂O₃. FIG. 30 also shows the region of interestof the dielectric layer analyzed. The region of interest excludes thetop surface of the dielectric layer and the interface between thedielectric layer and the substrate as well as the substrate itself. AlFand AlOH were chosen as representative of the types of species detectedwith this analysis technique. Other species can be used for detectionpurposes. Species that can be found at the interface in a dielectricstack can depend on a number of variables including the type oftreatment, the equipment used for treatment, the dielectric composition,substrate composition, and others.

As seen in FIG. 30, single layer films typically have profiles that aregenerally flat with intensity variations of less than 10%. The presenceof one or more peaks in the intensity signal is indicative of aninterface in the material that has received a treatment process. Changesin the intensity signal due to the treatment at the interface can alsobe valleys, or manifest as a reduction in signal from the baseline. Theanalysis of a film with multiple interfaces produces a signal containinga number of peaks (or intensity changes) corresponding to the number ofinterfaces. It is expected that one skilled in the art should be able todetect meaningful differences in the signal (peaks) over signal noisethat is associated with the analytical technique. Peaks that differ by50% or more from the baseline or valley are typical, although dependingon the amount of the species present and the sensitivity of thetechnique peaks can differ by 5000% or more. As seen in FIG. 30, thesignal associated with AlOH and the signal associated with AlF each havethree peaks corresponding to three interfaces contained within themultilayer dielectric stack. The signal associated with AlOH varies by60%, while the signal associated with AlF varies by about 10,800%. Thepresence of the peaks is a marker that indicates that an inorganicdielectric layer is indeed a patterned inorganic thin film dielectricstack and not a single layer of material.

A change in the intensity signal within the dielectric stack 450 for animpurity or compositional species that is 50% or greater is alsoindicative that the inorganic dielectric layer is indeed a patternedinorganic thin film dielectric stack 450 and not a single layer ofmaterial. As shown in FIG. 8 a, the thickness of the first inorganicthin film dielectric material layer 430 and the thickness of the secondinorganic thin film dielectric material layer 440 are same.Alternatively, the first inorganic thin film dielectric material layer430 and the second inorganic thin film dielectric material layer 440 candiffer in thickness. As shown in FIG. 8 a, the first inorganic thin filmdielectric material layer and the second inorganic thin film dielectricmaterial layer are in contact with each other.

FIG. 9 a is a cross-sectional diagram of an electronic element, takenalong the line A-A′ of the plan view shown in FIG. 9 b. The electronicelement of FIGS. 9 a and 9 b is similar to that shown in FIGS. 8 a and 8b. As shown in FIG. 9 b, on substrate 400, there is patterned firstelectrically conductive material 410 and patterned second electricallyconductive material 420 that overlap (in plan-view) at overlap regions425. In order to keep the first electrically conductive material 410 andsecond electrically conductive material 420 from electrically shorting,a patterned inorganic thin film dielectric stack 450 is disposed betweenthem. In this embodiment the patterned first inorganic thin filmdielectric material 470 has a different pattern from that of thepatterned second inorganic thin film dielectric material 460. As shownin FIGS. 9 a and 9 b, the patterned first inorganic thin film dielectricmaterial 470 has a larger area than that of the patterned secondinorganic thin film dielectric material 460, however it should beappreciated that this difference is for illustrative purposes and thatthe patterns of the first 470 and second 40 inorganic thin filmdielectric materials can have any desired relationship. The firstinorganic thin film dielectric material layer 470 and the secondinorganic thin film dielectric material layer 460 have the same materialcomposition.

FIG. 10 a is a cross-sectional diagram of an electronic element, takenalong the line A-A′ of the plan view shown in FIG. 10 b. The electronicelement of FIGS. 10 a and 10 b illustrate a likely outcome when actuallymanufacturing the electronic element depicted in FIGS. 8 a and 8 b. Asshown in FIG. 10 b, on substrate 400, there is patterned firstelectrically conductive material 410 and patterned second electricallyconductive material 420 that overlap (in plan-view) at overlap regions425. In order to keep the first electrically conductive material 410 andsecond electrically conductive material 420 from electrically shorting,a patterned inorganic thin film dielectric stack 450 is disposed betweenthem. As shown in FIGS. 10 a and 10 b, the patterned first inorganicthin film dielectric material 475 has the same pattern as that of thepatterned second inorganic thin film dielectric material 465 but thereis a misalignment of the two patterns. This misalignment can be anatural consequence of misalignment during applying or patterning thesecond deposition inhibitor pattern when the element is form from thecombination of SAD and ALD. Even “perfectly” aligned patterns withinmanufacturing tolerances often have edges that are detectably misalignedusing common analytical techniques, including simple optical microscopeinspection. The first inorganic thin film dielectric material layer 475and the second inorganic thin film dielectric material layer 465 havethe same material composition.

In semiconductor processing, it is sometimes desirable to have twolayers of different materials that have the same pattern. Depending onthe composition of the two layers, it may not be easy to uniformlydeposit and then pattern the materials. In FIG. 4, a diagrammatic Stepdiagram is shown for one embodiment of a process of the presentinvention for making a patterned thin film inorganic material stackusing a combination of selected area deposition (SAD) and ALD. As shownin Step 1, a substrate is supplied into the system. In Step 10 adeposition inhibitor material is deposited. The deposition inhibitormaterial can generically be any material that causes the materialdeposition to be inhibited and should be understood from the previousdescriptions. In one embodiment, the deposition inhibitor material ischosen specifically for the material to be deposited. In otherembodiments, the deposition inhibitor material has a given inhibitionpower. The inhibition power is defined as the layer thickness at orbelow which the deposition inhibitor material is effective. Thedeposition of the deposition inhibitor material in Step 10 can be in apatterned manner, such as using inkjet, flexography, gravure printing,micro-contact printing, offset lithography, patch coating, screenprinting, or transfer from a donor sheet. In an alternative embodiment,Step 10 can deposit a uniform layer of the deposition inhibitor materialand Step 15 can be optionally employed to form a patterned layer of thedeposition inhibitor material.

Continuing with FIG. 4, Step 22 deposits the desired first thin filmmaterial by an Atomic Layer Deposition (ALD) process. Generically thisdeposition can be using any ALD system, preferably a spatial ALD system.The first thin film material is deposited only in the areas of thesubstrate where there is no deposition inhibitor material. After thefirst thin film dielectric material is deposited in Step 22, a secondthin film material layer is deposited by ALD in Step 52. The second thinfilm material is deposited only in the areas of the substrate wherethere is no deposition inhibitor material, and as such is patterned intothe same pattern as the first thin film material layer. The second thinfilm dielectric material is different in composition from that of thefirst thin film dielectric material. The layer thickness of the firstand second thin film inorganic materials can be the same or different.

After depositing the second thin film material, the deposition inhibitormaterial can be optionally removed in Step 60. The deposition inhibitorcan be removed by a liquid process using a solvent or a detergent. Theliquid process can utilize a mechanical action such as brushing orwiping or pressure jets. The deposition inhibitor can also be removed bya vapor process. These processes include exposing the substrate to avapor reactant that causes removal of the inhibitor. The removal canhappen spontaneously upon reaction with the vapor, resulting in theconversion of the inhibitor to a volatile species. Alternatively, thevapor exposure can react with the inhibitor converting it to anotherspecies or morphology that is then more easily removable with anotherprocess, such as a liquid process. The vapor exposure can include formsof energy to promote the process. These include light exposure, and arcsor plasmas. Particularly desired light exposures include UV exposure,especially in the presence of oxygen to produce ozone. Plasmas includeplasmas of various species including oxygen, chlorine, and fluorine.Plasmas created with these materials or with precursors that producethese materials are included in the present invention.

FIGS. 6 a through 6 e are a schematic diagram for one embodiment of amethod of producing an inorganic multi-layered thin film structure usinga combination of selected area deposition (SAD) and ALD and the processdescribed in FIG. 4. FIG. 6 a shows a substrate 300. FIG. 6 b shows theapplication the patterned deposition inhibiting material layer 310 tosubstrate 300, leaving region 315 where the deposition inhibitingmaterial layer is not present. FIG. 6 c shows the result of depositionof a first inorganic thin film 320 by an Atomic Layer Deposition (ALD)process on the substrate, resulting in patterned deposition of the firstinorganic thin film in regions 315 and little to no deposition of thefirst inorganic thin film in areas covered by deposition inhibitor 310.FIG. 6 d shows the result of deposition of a second inorganic thin filmby an Atomic Layer Deposition (ALD) process on the substrate, resultingin patterned second inorganic thin film material 330 in the same areas315 as the first inorganic thin film and little to no deposition of thesecond inorganic thin film in areas covered by deposition inhibitor 310.The resulting inorganic multi-layered thin film structure 350 nowincludes a stack of two inorganic thin films. FIG. 6 e shows thesubstrate after an optional removal of the deposition inhibitor, leavingsubstantially only the inorganic multi-layered thin film structures 350on the original substrate 300.

The first inorganic thin film material layer 320 and the secondinorganic thin film material layer 330 can have different materialcompositions. The difference in material composition can includedifferences in one or more of the atomic constituents that compose theinorganic thin film. The difference in composition can include only achange in the atomic ratio of the constituents that compose theinorganic thin film.

The first inorganic thin film material layer 320 can include adielectric material and the second inorganic thin film material layercan include a semiconductor material 330, wherein selectively depositingthe second inorganic thin film material layer includes selectivelydepositing the second inorganic thin film material layer on the firstinorganic thin film material layer after the first inorganic thin filmmaterial layer has been deposited on the substrate. Alternatively, thefirst inorganic thin film material layer 320 is a semiconductor materialand the second inorganic thin film material layer 330 is a dielectricmaterial, and selectively depositing the second inorganic thin filmmaterial layer includes selectively depositing the second inorganic thinfilm material layer on the first inorganic thin film material layerafter the first inorganic thin film material layer has been deposited onthe substrate.

FIG. 11 a is a cross-sectional diagram of one embodiment of a TFT 500 ofthe present invention, taken along the line A-A′ of the plan view shownin FIG. 11 b. The TFT 500 shown in FIGS. 11 a and 11 b is a bottom gatestructure that is representative of any bottom gate TFT 500 where thegate 520 is in contact with the substrate, the first inorganic thin filmdielectric layer 530 is in contact with the gate and the substrate, thesecond inorganic thin film dielectric layer 540 is in contact with thefirst inorganic thin film dielectric layer 530, and the semiconductorlayer is in contact with the source/drain 580. As shown in FIG. 11 b, onsubstrate 510, there is a gate 520 including a first electricallyconductive layer stack. The substrate 510 can be any previouslydiscussed substrate, and can contain a plurality of predefined layers.The gate has the conventionally accepted meaning, and is used to gatethe current of the TFT. The first electrically conductive layer stack ofthe gate 520 can be a single conductive material, as shown in FIG. 11 a,or can include any number of conductive material layers.

In order to keep the gate isolated from the source/drain electrode 580,a patterned inorganic thin film dielectric stack 550 is disposed betweenthem. Patterned inorganic thin film dielectric stack 550 is made up ofpatterned first inorganic thin film dielectric material layer 530 andpatterned second inorganic thin film dielectric material layer 540. Thefirst inorganic thin film dielectric layer 530 has a first pattern andthe second inorganic thin film dielectric layer 540 has a first pattern.As shown in FIG. 11 b, the patterns of the first 530 and second 540inorganic thin film dielectric material layers are the same pattern andhave the same material composition. In alternative embodiments, thepatterns of the first 530 and second 540 patterned inorganic thin filmdielectric layers can be different, or the same but misaligned in themanufacturing process. Although the patterned first inorganic thin filmdielectric material 530 and patterned second inorganic thin filmdielectric material 540 have the same material composition, they do nothave the same analytical signature as a single layer with a combinedthickness of the same material. As discussed previously, a change incomposition can be detected in the contact region using depth profilingtechniques. When an intensity signal for an impurity or compositionalspecies in a contact area between the first inorganic thin filmdielectric material layer and the second inorganic thin film dielectricmaterial layer differs by 50% or more when compared to the intensitysignal outside of the contact region, it serves as a marker indicatingthat an inorganic dielectric layer is indeed a patterned inorganic thinfilm dielectric stack 550 and not a single layer of material.

The interface between the semiconductor and the dielectric is criticalto the function of the TFT. Depending upon the manufacturing methodsused to make the TFT, this interface may or may not be easilycontrolled. In TFTs that are formed by the combination of SAD and ALD,special care should be taken to insure that when changing between thedielectric pattern and the semiconductor pattern the interface is notdisturbed by the removal of the deposition inhibiting material. As shownin FIG. 11 a a patterned third inorganic thin film dielectric layer 560,also referred to as a buffer layer, is present in the device. The thirdpatterned inorganic thin film dielectric layer 560 has a third patternthat is located within an area defined by at least one of the first andsecond patterns of the first 530 and second 540 inorganic thin filmdielectric material layers. The patterned semiconductor layer 570 is incontact with and has the same pattern as the patterned third inorganicthin film dielectric material layer 560. The patterned third inorganicthin film dielectric material layer 560 can be a different material asthe patterned inorganic thin film dielectric stack 550. The patternedthird inorganic thin film dielectric material layer 560 can preferablybe the same material as the patterned inorganic thin film dielectricstack 550. In this case the interface can be detected (as discussedabove) by a change in the intensity signal of either an impurity orcompositional species from the baseline signal of the patterned thirdinorganic thin film dielectric material layer 560 and the patternedsecond inorganic thin film dielectric material layer 540. A change inthe intensity signal for an impurity or compositional of 50% or greaterindicates that an inorganic dielectric layer is indeed a patternedinorganic thin film dielectric stack 550 and not a single layer ofmaterial.

FIGS. 11 a and 11 b show the relative location of the source/drainelectrodes 580 on substrate 510. The source and drain haveconventionally accepted meanings, and either electrode shown can bedesignated the source (or drain) as is required by the application orcircuit. The source/drain 580 includes a second electrically conductivelayer stack. As with the first electrically conductive stack, the secondelectrically conductive layer stack is a single conductive material, asshown in FIG. 11 a, or can include any number of conductive materiallayers.

FIG. 12 a is a cross-sectional diagram of another embodiment of a TFT505 of the present invention, taken along the line A-A′ of the plan viewshown in FIG. 12 b. The TFT 505 shown in FIGS. 12 a and 12 b is a topgate structure that is representative of any top gate TFT 505 where thesource/drain 580 is in contact with the substrate, the semiconductorlayer 570 is in contact with the source/drain 580 and the substrate 510,the second inorganic thin film dielectric layer 540 is in contact withthe first inorganic thin film dielectric layer 530, and is in contactwith the gate 520.

As shown in FIG. 12 b, on substrate 510, there is a gate 520 including afirst electrically conductive layer stack. The substrate 510 can be anypreviously discussed substrate, and can contain a plurality ofpredefined layers. The gate has the conventionally accepted meaning, andis used to gate the current of the TFT 505. The first electricallyconductive layer stack of the gate 520 can be a single conductivematerial, as shown in FIG. 12 a, or can include any number of conductivematerial layers.

In order to keep the gate isolated from the source/drain electrode 580,a patterned inorganic thin film dielectric stack 550 is disposed betweenthem. Patterned inorganic thin film dielectric stack 550 is made up ofpatterned first inorganic thin film dielectric material layer 530 andpatterned second inorganic thin film dielectric material layer 540.These layers should be easily understood from their descriptions inreference to FIGS. 11 a and 11 b.

As with the bottom gate TFT 500 of FIGS. 11 a and 11 b, the interfacebetween the semiconductor and the dielectric is critical to the functionof the top gate TFT 505. As shown in FIG. 12 a a patterned thirdinorganic thin film dielectric layer 560, also referred to as a bufferlayer, is present in this top gate TFT 505. The patterned semiconductorlayer 570 is in contact with and has the same pattern as the patternedthird inorganic thin film dielectric material layer 560. As shown inFIG. 12 a, the patterned semiconductor layer 570 is in contact withsubstrate 510 in this top gate TFT 505. These layers should beunderstood from their descriptions with respect to FIGS. 11 a and 11 b.

FIGS. 12 a and 12 b show the relative location of the source/drainelectrodes 580 on substrate 510. The source and drain have theconventionally accepted meaning, and either electrode shown can bedesignated the source (or drain) as is required by the application orcircuit.

FIG. 13 a is a cross-sectional diagram of another embodiment of a TFT600 of the present invention, taken along the line A-A′ of the plan viewshown in FIG. 13 b. The TFT 600 shown in FIGS. 13 a and 13 b is a bottomgate structure similar to that shown in FIGS. 11 a and 11 b. The TFT 600of FIGS. 13 a and 13 b is illustrative of an embodiment of the presentinvention where the interface between the dielectric and semiconductoris controlled by a buffer layer, but uses a single layer of dielectricwith sufficient quality. In this embodiment, TFT 600 has a gate 620 thatis in contact with the substrate 610, a first inorganic thin filmdielectric layer 630 is in contact with the gate and the substrate, asecond inorganic thin film dielectric layer 660 is in contact with thefirst inorganic thin film dielectric layer 630, and a semiconductorlayer 670 is in contact with the source/drain 680. TFT 600 shown inFIGS. 13 a and 13 b is a bottom gate structure, but it should beunderstood that transistors with a top gate structure composed of thesame layers can be constructed and are considered an alternativeembodiment of the present invention. Such a top gate TFT of the presentinvention has a source/drain 680 in contact with the substrate 610,semiconductor layer 670 that is in contact with the source/drain 680 andthe substrate 610, a second inorganic thin film dielectric layer 660that is in contact with the first inorganic thin film dielectric layer630, and a first inorganic thin film dielectric layer 630 that is incontact with the gate 620.

As shown in FIG. 13 b, on substrate 610, there is a gate 620 including afirst electrically conductive layer stack. The substrate 610 can be anypreviously discussed substrate, and can contain a plurality ofpredefined layers. The gate has the conventionally accepted meaning, andis used to gate the current of the TFT. The first electricallyconductive layer stack of the gate 620 can be a single conductivematerial, as shown in FIG. 13 a, or can include any number of conductivematerial layers.

In order to keep the gate isolated from the source/drain electrode 680,a first patterned inorganic thin film dielectric layer 630 is disposedbetween them. The first inorganic thin film dielectric layer 630 has afirst pattern as shown in FIGS. 13 a and 13 b. As previously discussed,the interface between the semiconductor and the dielectric is criticalto the function of the TFT. FIGS. 13 a and 13 b shown a patterned secondinorganic thin film dielectric layer 660, also referred to as a bufferlayer located between the first patterned inorganic thin film dielectriclayer 630 and the semiconductor layer 670. The second patternedinorganic thin film dielectric layer 670 has a second pattern that islocated within an area defined by first pattern of the first inorganicthin film dielectric material layer 630.

As shown in FIG. 13 a, the patterned semiconductor layer 670 is incontact with and has the same pattern as the patterned second inorganicthin film dielectric material layer 660. The patterned second inorganicthin film dielectric material layer 660 can be a different material thanthat of the first patterned inorganic thin film dielectric layer 630.The patterned second inorganic thin film dielectric material layer 660is preferably the same material as the first patterned inorganic thinfilm dielectric layer 630. In this case the interface can be detected(as discussed above) by a change in the intensity signal of either animpurity or compositional species from the baseline signal of thepatterned second inorganic thin film dielectric material layer 660 andthe patterned first inorganic thin film dielectric material layer 630. Achange in the intensity signal for an impurity or compositional speciesof 50% or greater indicates that an inorganic dielectric layer is madeup of a first patterned inorganic thin film dielectric layer 630 andpatterned second inorganic thin film dielectric material layer 660, andwas not deposited as a single dielectric layer.

FIGS. 13 a and 13 b show the relative location of the source/drainelectrodes 680 on substrate 610. The source and drain have theconventionally accepted meaning, and either electrode shown can bedesignated the source (or drain) as is required by the application orcircuit. The source/drain 680 includes a second electrically conductivelayer stack. As with the first electrically conductive stack, the secondelectrically conductive layer stack a single conductive material, asshown in FIG. 13 a, or can include any number of conductive materiallayers.

FIG. 14 a is a cross-sectional diagram of another embodiment of a TFT700 of the present invention, taken along the line A-A′ of the plan viewshown in FIG. 14 b. The TFT 700 shown in FIGS. 14 a and 14 b is a bottomgate structure similar to that shown in FIGS. 11 a and 11 b. The TFT 700of FIGS. 14 a and 14 b is illustrative of an embodiment of the presentinvention of where a buffer layer is not required to control theinterface and a multilayer dielectric stack is used. In this embodiment,TFT 700 has a gate 720 is in contact with the substrate 710, a firstinorganic thin film dielectric layer 730 that is in contact with thegate 720 and the substrate 710, a second inorganic thin film dielectriclayer 740 that is in contact with the semiconductor layer 770, and asemiconductor layer 770 that is in contact with the source/drain 780.TFT 700 shown in FIGS. 14 a and 14 b is a bottom gate structure, but itshould be understood that transistors with a top gate structure composedof the same layers can be constructed and are considered an alternativeembodiment of the present invention. A top gate TFT of the presentinvention has a source/drain 780 that is in contact with the substrate710, a semiconductor layer 770 that is in contact with the source/drain780 and the substrate 710, a first inorganic thin film dielectric layer730 is in contact with the semiconductor layer 770, and a secondinorganic thin film dielectric layer 740 that is in contact with thegate.

As shown in FIG. 14 b, on substrate 710, there is a gate 720 including afirst electrically conductive layer stack. The substrate 710 can be anypreviously discussed substrate, and can contain a plurality ofpredefined layers. The gate has the conventionally accepted meaning, andis used to gate the current of the TFT. The first electricallyconductive layer stack of the gate 720 can be a single conductivematerial, as shown in FIG. 14 a, or can include any number of conductivematerial layers.

In order to keep the gate 720 isolated from the source/drain electrode780, a patterned inorganic thin film dielectric stack 750 is disposedbetween them. Patterned inorganic thin film dielectric stack 750 is madeup of patterned first inorganic thin film dielectric material layer 730and patterned second inorganic thin film dielectric material layer 740.The first inorganic thin film dielectric layer 730 has a first patternand the second inorganic thin film dielectric layer 740 has a secondpattern. As shown in FIG. 14 b, the patterns of the first 730 and second740 inorganic thin film dielectric material layers are the same patternand have the same material composition. In alternative embodiments, thepatterns of the first 730 and second 740 patterned inorganic thin filmdielectric layers be different, or the same but misaligned as a resultof the manufacturing process. Although the patterned first inorganicthin film dielectric material 730 and patterned second inorganic thinfilm dielectric material 740 have the same material composition, they donot have the same analytical signature as a single layer with a combinedthickness of the same material. As discussed previously, there is achange in the intensity signal of either an impurity or compositionalspecies in the contact region when compared to a region of the firstinorganic thin film dielectric material layer 730 and the secondinorganic thin film dielectric material layer 740 that is outside of thecontact region. This intensity change acts as a marker indicating thatan inorganic dielectric layer is indeed a patterned inorganic thin filmdielectric stack 750 and not a single layer of material. When anintensity signal for an impurity or compositional species in a contactarea between the first inorganic thin film dielectric material layer 730and the second inorganic thin film dielectric material layer 740 differsby 50% or more when compared to the intensity signal outside of thecontact region, it serves as a marker indicating that the inorganicdielectric layer is not a single layer of material. The first inorganicthin film dielectric material layer 730 and the second inorganic thinfilm dielectric material layer each have an associated thickness, and asshown in FIG. 14 a the thickness of the first inorganic thin filmdielectric material layer 730 and the thickness of the second inorganicthin film dielectric material layer 740 are same. In alternativeembodiments of the present inventions these film thickness can bedifferent.

As shown in FIG. 14 a, the patterned semiconductor layer 770 is incontact with the patterned second inorganic thin film dielectricmaterial layer 740. The patterned semiconductor layer 770 has a thirdpattern and that third pattern is located within an area defined byfirst pattern of the first inorganic thin film dielectric material layer730.

FIGS. 14 a and 14 b show the relative location of the source/drainelectrodes 780 on substrate 710. The source and drain have theconventionally accepted meaning, and either electrode shown can bedesignated the source (or drain) as is required by the application orcircuit. The source/drain 780 includes a second electrically conductivelayer stack. As with the first electrically conductive stack, the secondelectrically conductive layer stack a single conductive material, asshown in FIG. 14 a, or can include any number of conductive materiallayers.

EXAMPLES

Description of the Coating Apparatus

All of the following thin film examples employ a flow setup as indicatedin FIG. 28. The flow setup is supplied with nitrogen gas flow 81 thathas been purified to remove oxygen and water contamination to below 1ppm. The gas is diverted by a manifold to several flow meters whichcontrol flows of purge gases and of gases diverted through bubblers toselect the reactive precursors. In addition to the nitrogen supply,ammonia flow 90 is also delivered to the apparatus.

The following flows are delivered to the ALD coating apparatus: metal(zinc) precursor flow 92 containing metal precursors diluted in nitrogengas; oxidizer-containing flow 93 containing non-metal precursors oroxidizers diluted in nitrogen gas; and nitrogen purge flow 95 composedonly of the inert gas. The composition and flows of these streams arecontrolled as described below.

Gas bubbler 83 contains liquid dimethylaluminum isopropoxide (DMAI) andgas bubbler 82 contains diethyl zinc (DEZ). Flow meter 86 and flow meter85 deliver flows of pure nitrogen to the bubblers. The output of thebubbler now contains nitrogen gas saturated with the respectiveprecursor solution. The output flow is mixed with a nitrogen gasdilution flow delivered from flow meter 87 to yield the overall flow ofmetal precursor flow 92. In the following examples, the flows for thedielectric material are as follows:

Flow meter 86: To Dimethylaluminum isopropoxide Bubbler Flow

Flow meter 87: To Metal Precursor Dilution Flow

Gas bubbler 84 contains pure water at room temperature. Flow meter 88delivers a flow of pure nitrogen to gas bubbler 84, the output of whichrepresents a stream of saturated water vapor. An ammonia flow iscontrolled by flow meter 91. The water bubbler output and air streamsare mixed with dilution stream from flow meter 89 to produce the overallflow of oxidizer-containing flow 93 which has a variable water vaporcomposition, nitrogen composition, and total flow. In the followingexamples, the flows are as follows:

Flow meter 88: To Water Bubbler

Flow meter 89: Oxidizer Dilution Flow

Flow meter 91: Ammonia Flow

Flow meter 94 controls the flow of pure nitrogen that is to be deliveredto the coating apparatus. Streams or Flows 92, 93, and 95 are thendelivered to an atmospheric pressure coating head where they aredirected out of the channels or microchamber slots as indicated in FIG.29. A gap 99 exists between the elongated channels and the substrate 97.Substrate 97 is maintained in close proximity to the output face 105 byan equilibrium between the flow of the gases supplied to the output faceand a slight amount of vacuum produced at the exhaust slot.

In order to perform a deposition, the delivery head 100 is positionedover a portion of the substrate 97 and then moved in a reciprocatingfashion over the substrate 97, as represented by the arrow 98. Thelength of the reciprocation cycle was 32 mm. The rate of motion of thereciprocation cycle was varied as a deposition parameter.

Materials Used:

(1) Glass substrates, cut to 2.5×2.5″ squares, previously cleaned inPiranha solution, washed with distilled water, reagent ethanol anddried.

(2) Dimethylaluminum isopropoxide (DMAI) (commercially available fromStrem Chemical Co.).

(3) Diethylzinc (DEZ) (commercially available from Strem Chemical Co.).

(4) Polyvinylpirolidone (PVP) k-30 (commercially available from AcrosOrganics).

General Conditions for the Preparation of Layers Using AtmosphericPressure ALD

This describes the preparation of a thin film coating of the materiallayers on glass substrates as used in the examples. The ALD coatingdevice used to prepare these layers, namely Al₂O₃, ZnO:N, and Al-dopedZnO (AZO), has been described in detail in US Patent ApplicationPublication No. US 2009/0130858, the disclosure of which is incorporatedby reference herein in its entirety. The coating device has an outputface 105 (facing up as shown in FIG. 29) that contains spatiallyseparated elongated gas channels and operates on a gas bearingprinciple. Each gas channel is composed of an output slot 95, 93, 92which supplies gas to the output face 105, and adjacent exhaust slots110 which remove gas from the output face 105. The order of the gaschannels is P-O-P-M-P-O-P-M-P-O-P where P represents a purge channel, Orepresents a channel containing an oxygen based precursor, and Mrepresents a channel containing a metal based precursor. As a substratemoves relative to the coating head it sees the above sequence of gaseswhich effects and ALD deposition.

A 2.5×2.5 inch square (62.5 mm square) substrate 97, attached to aheated backer, is positioned on the output face of the coating deviceand is maintained in close proximity to the output face by anequilibrium between the flow of the gases supplied to the output faceand a slight amount of vacuum produced at the exhaust slot. For all ofthe examples, the exhaust slot pressure was approximately 40 inches ofwater below atmospheric pressure. The purge gas P is composed of purenitrogen. The oxygen reactive precursor O is a mixture of nitrogen,water vapor, and optionally ammonia vapor. The metal reactive precursorM is one or a mixture of active metal alkyls vapor in nitrogen.

The metal alkyl precursors used in these examples were dimethylaluminumisopropoxide (DMAI) and diethyl zinc (DEZ). The flow rate of the activemetal alkyl vapor was controlled by bubbling nitrogen through the pureliquid precursor contained in an airtight bubbler by means of individualmass flow control meters. This saturated stream of metal alkyl was mixedwith a dilution flow before being supplied to the coating device. Theflow of water vapor was controlled by adjusting the bubbling rate ofnitrogen passed through pure water in a bubbler. This saturated streamof water vapor was mixed with a dilution flow before being supplied tothe coating device. The flow of ammonia vapor was controlled by passingpure ammonia vapor from a compressed fluid tank through and mass flowcontroller and mixing with the water vapor stream. All bubblers weremaintained at 22 C. The temperature of the coating was established bycontrolling heating both the coating device and the backer to a desiredtemperature. Experimentally, the flow rates of the individual gasseswere adjusted to the settings shown in Table 1 for each of the materiallayers coated in the examples contained herein. The flows shown are thetotal flows supplied to the coating device, and thus are partitionedequally among the individual gas channels.

The coating process was then initiated by oscillating 98 the coatinghead across the substrate for the number of cycles necessary to obtain auniform deposited film of the desired thickness for the given example.Due to the fact that the coating head as described above contains twofull ALD cycles (two oxygen and two metal exposures per single directionpass over the head), a round trip oscillation represents 4 ALD cycles.

TABLE 1 N₂ dilution N₂ DMAI DEZ Water with dilution N₂ bubbler bubblerNH3 bubbler Metal with Inert Residence Substrate flow flow flow flowAlkyl water Purge Time Temperature, Layer (sccm) (sccm) (sccm) (sccm)(sccm) (sccm) (sccm) (ms) ° C. Al₂O₃ 65 0 0 65 1500 2250 3000 100 or 50200 ZnO:N 0 60 4 45 1500 2250 3000 50 200 AZO 10 30 0 22.5 1500 22503000 50 200 or 250Cross-Over Experiments to Probe Dielectric Quality

In order to probe the quality of the dielectric layer, a number ofexperiments were run. The simplest experiments wereconductor-dielectric-conductor structures, with each sample substratehaving a large number of devices. These samples were evaluated for %yield, where % yield is defined as the percentage of devices that werenot dead shorts, and break-down voltage, where the break-down voltage isdefined as the voltage required for 5 nA of current. To obtain thesevalues, the voltage on the pattered top conductor was swept, while thebottom conductor was grounded. A detailed description of the samples andtheir respective testing conditions follows.

Comparative Example C1

Cross-Over with Single Layer of Dielectric

A glass substrate was prepared to have a conductor-dielectric-conductorstructure using the equipment described above. Prior to depositing thefirst thin film conductor, an aluminum stripe was deposited byevaporation through a shadow mask such that there was a aluminum stripealong one edge of the sample that extended beyond the ALD area to allowfor easy access to probe the bottom conductor. 1000 Å of AZO was thendeposited on the clean glass substrate having the aluminum stripe, at250 C and using 684 ALD cycles at the conditions listed for AZO in Table1 on the Atmospheric ALD equipment described above. Next, 520 Å of Al₂O₃was deposited in a single coating event at 200° C., using the conditionslisted for Al₂O₃ in Table 1 and 1856 ALD cycles each with a 50 msresidence time on the Atmospheric ALD equipment described above. Thesubstrate was then cleaned using 2 minutes of exposure to O₂ plasma, anda pattern of inhibitor ink was applied using a Fuji Dimatix 2500piezo-inkjet printer. The inhibitor ink was a 2 wt % solution of PVPk-30 in diacetone alcohol, and the pattern printed was a regular grid of350 μm by 350 μm openings on 700 μm centers. Following the patterning ofthe inhibitor, the substrate was returned to the Atmospheric ALDequipment and a second layer of 1000 Å of AZO was first deposited as thefirst, at 250 C and using 684 ALD cycles. Due to the presence of the PVPinhibitor, the AZO only deposited in the open areas of the pattern wherethe PVP was not present, forming a 12×73 grid of cross-over devices. Thesample was then subjected to a 2 minute O₂ plasma treatment to removethe PVP inhibitor. Testing of the cross-over was accomplished by using aprobe station to contact the aluminum stripe for the bottom contact andthe patterned AZO, results can be found in Table 2.

Inventive Example I1

Cross-Over with Two Layer Dielectric, with an O₂ Plasma at the Interface

Inventive example I1, was prepared as comparative example C1 with thefollowing exception. Instead of depositing 520 Å of Al₂O₃ in a singlecoating event, the dielectric layer was divided into two layers.Experimentally, 260 Å of Al₂O₃ was deposited at 200° C., using theconditions listed for Al₂O₃ in Table 1 and 928 ALD cycles each with a 50ms residence time on the Atmospheric ALD equipment described above. Nextthe sample was subjected to a 2 minute O₂ plasma treatment to clean theinterface between the two layers of Al₂O₃ and reset the surface. Afterthe O₂ plasma, another 260 Å of Al₂O₃ was deposited using the sameconditions as the first layer. The sample was completed and tested as incomparative example C1, results can be found in Table 2.

Inventive Example I2

Cross-Over with Two Layer Dielectric, with an Ambient Hold Treatment atthe Interface

Inventive example I2, was prepared as inventive example I1 with thefollowing exception. Instead of treating the interface with O₂ plasma,the sample was instead held for 5 minutes at ambient lab conditions,nominally treating the sample surface to equilibrate in a higherhumidity environment and reset the surface or the Al₂O₃. After theambient treatment, another 260 Å of Al₂O₃ was deposited using the sameconditions as the first layer. The sample was completed and tested as incomparative example C1, results can be found in Table 2.

Inventive Example I3

Cross-Over with Two Layer Dielectric, with UV-Ozone Cleaning at theInterface

Inventive example I3, was prepared as inventive example I1 with thefollowing exception. Instead of treating the interface with O₂ plasma,the sample was instead subjected to a 15 minute UV-ozone clean. Afterthe ambient treatment, another 260 Å of Al₂O₃ was deposited using thesame conditions as the first layer. The sample was completed and testedas in comparative example C1, results can be found in Table 2.

TABLE 2 Number of Number Break- Sam- Dielectric Layer devices bad Down %ple Details tested devices Voltage Yield C1 Single Layer 1241 166 20.686.6 I1 Double layer with O₂ 1241 44 20.6 96.5 plasma treatment atinterface I2 Double layer with ambi- 1241 72 21.4 94.2 ent holdtreatment at interface I3 Double layer with UV- 1241 112 21.0 91 ozonetreatment at interface

As can be seen in Table 2, all inventive samples I1 through I2 hadhigher yield than the comparative example C2. As seen in Table 2,inventive sample I1 with an O₂ plasma at the interface gave the biggestyield improvement, and as such is one of the preferred embodiments ofthe preset invention.

Comparative Example C2

Cross-Over with Single Layer of Dielectric

Comparative example C2, was prepared as comparative example C1 with thefollowing exception. Instead of depositing 520 Å of Al₂O₃, 800 Å wasdeposited in a single coating event. This was done experimentally at200° C. by using the conditions listed for Al₂O₃ in Table 1 and 1856 ALDcycles each with a 100 ms residence time on the Atmospheric ALDequipment described above. Next the sample was subjected to a 2 minuteO₂ plasma treatment to clean the interface between the two layers ofAl₂O₃ and reset the surface. After the O₂ plasma, another 260 Å of Al₂O₃was deposited using the same conditions as the first layer. The samplewas completed and tested as in comparative example C1, results can befound in Table 3.

Inventive Example I4

Cross-Over with Two Layer Dielectric, with an O₂ Plasma at the Interface

Inventive example I4, was prepared as comparative example C2 with thefollowing exception. Instead of depositing 800 Å of Al₂O₃ in a singlecoating event, the dielectric layer was divided into two layers.Experimentally, 400 Å of Al₂O₃ was deposited at 200° C., using theconditions listed for Al₂O₃ in Table 1 and 928 ALD cycles each with a100 ms residence time on the Atmospheric ALD equipment described above.Next the sample was subjected to a 2 minute O₂ plasma treatment to cleanthe interface between the two layers of Al₂O₃ and reset the surface.After the O₂ plasma, another 400 Å of Al₂O₃ was deposited using the sameconditions as the first layer. The sample was completed and tested as incomparative example C2, results can be found in Table 3.

Inventive Example I5-I9

Cross-Over with Multi Layer Dielectric, with an O₂ Plasma at theInterface(s)

Inventive examples I5 through I9 were prepared as I4, only instead ofdividing the 800 Å of Al₂O₃ equally into two layers, the dielectric wasdivided in various ways—with each sample receiving a 2 minute O₂ plasmatreatment at the interface between subsequent layers of Al₂O₃ to cleanand reset the surface. The details of inventive samples I5-I9 can befound in Table 3, along with the results of the electrical testing.Sample I9 had less devices printed, and therefore less devices tested,however statistical comparison should still be valid.

TABLE 3 Number of Number Break- Sam- Dielectric Layer devices bad Down %ple Details tested devices Voltage Yield C2 Single Layer 1241 1026 2717.3 I4 Double layer (400 Å/400 Å) 1241 57 30 95.4 with O₂ plasmatreatment at interface I5 Double layer (100 Å/700 Å) 1241 22 32 98.2with O₂ plasma treatment at interface I6 Double layer (700 Å/100 Å) 124154 28 95.6 with O₂ plasma treatment at interface I7 Triple layer (266Å/267 Å/ 1241 47 31 96.2 267 Å) with O₂ plasma treatment at interfacesI8 Triple layer (100 Å/600 Å/ 1241 59 32 95.2 100 Å) with O₂ plasmatreatment at interfaces I9 Quadruple layer 876 14 32 98.4 (200 Å/200Å/200 Å/ 200 Å) with O₂ plasma treatment at interfaces

As can be seen in Table 3, all inventive samples I4 through I9 had asignificantly higher yield than the comparative example C2. All sampleswere run in spatial ALD equipment that was located in a standardchemical hood, in a non-clean room environment. While the data shows nostatistical improvement in the yield between the embodiments of theinventive samples under the conditions run, the data does suggest thathaving a thin layer nearest to the ground electrode can be preferred.

Comparative Example C3

Single Layer Dielectric on a Glass Substrate

Comparative example C3, was prepared in order facilitate analysis of adielectric layer composition through time-of-flight secondary ion massspectroscopy (ToF SIMS). Experimentally, a clean glass substrate wascoated with 800 Å of Al₂O₃ in a single coating event at 200° C., usingthe conditions listed for Al₂O₃ in Table 1 and 1856 ALD cycles each witha 100 ms residence time on the Atmospheric ALD equipment describedabove. The dielectric layer of comparative example C3 is equivalent tothat of comparative example C2. Positive-ion SIMS depth profiles of thesample were obtained using an ION TOF IV ToF-SIMS instrument. AnArgon-ion gun (40 nA at 3 keV and 10 s/cycle) was used to sputter a 225μm by 225 μm area on the sample. Between each sputter cycle a 75 μm by75 μm area co-centered within the sputtered area was then analyzed usinga pulsed Bi₃ ⁺ liquid metal ion gun (0.3 pA at 25 keV). To enhance thesignals for metal ions and to help with stabilizing the sample surfacecharge an O₂ gas flood was directed at the sample and adjusted until asteady pressure of 10⁻⁶ mBar was measured in the analysis chamber. Fourspecies from the positive analysis (AlF, B, AlOH and Si) were selectedto illustrate the types of ToF SIMS signatures that can be found whenanalyzing single layer and multilayer dielectric materials. For eachspecies, the number of peaks was counted and the average percent changein intensity from peak to valley was calculated. This calculation wasconstrained to exclude species at the top surface and at the interfacewith the substrate (the interface of the substrate is clearlyidentifiable by a substantial change in composition). Additionally, thepercent change in intensity was only calculated when a peak wasdetected. The percent change in peak intensity can be positive ornegative. In this analysis only the relative magnitude of the change isreported. The results of the number of peaks counted and the averagepercent change in the ToF SIMS can be found in Table 5. FIG. 30 containsthe data for the AlF and AlOH signals of comparative example C3 thatwere used to calculate the values in Table 5 for those species.

Inventive Example I10

Four Layer Dielectric on a Glass Substrate

Inventive example I10, was prepared as comparative example C3 with thefollowing exception. Instead of depositing 800 Å of Al₂O₃ in a singlecoating event, the dielectric layer was divided into four layers.Experimentally, 200 Å of Al₂O₃ was deposited at 200° C., using theconditions listed for Al₂O₃ in Table 1 and 928 ALD cycles each with a100 ms residence time on the Atmospheric ALD equipment described above.Next the sample was subjected to a 2 minute 100 W 0.3 Torr O₂ plasmatreatment to clean the interface between the two layers of Al₂O₃ andreset the surface. After the O₂ plasma, another 200 Å of Al₂O₃ wasdeposited using the same conditions as the first layer. This wasrepeated twice more until the overall layer thickness was 800 Å. Thedielectric layer of comparative example I10 has interlayer interfacesthat are equivalent to those of inventive example I4. Inventive exampleI10 was analyzed as described in comparative example C3, with theaddition of three species selected from negative ion analysis (AlO₂, F,and CN) to further illustrate the types of ToF SIMS signatures that canbe found when analyzing multilayer dielectric materials. The results ofthe number of peaks counted and average percent change in the ToF SIMScan be found in Table 5. FIG. 30 contains the data for the AlF and AlOHsignals of inventive example I10 that were used to calculate the valuesin Table 5 for those species.

INVENTIVE EXAMPLE I11

Four Layer Dielectric on a Silicon Substrate

Inventive example I11, was prepared as inventive example I10 with theexception that the sample was coated onto clean silicon substrateinstead of a glass substrate. Inventive example I11 was analyzed asdescribed in inventive example I10. The results of the number of peakscounted and average percent change in the ToF SIMS can be found in Table5.

Inventive Example I12

Four Layer Dielectric on a Glass Substrate

Inventive example I12, was prepared as inventive example I10 with thefollowing exceptions. Instead of subjecting the sample to a 2 minute 100W 0.3 Torr O₂ plasma treatment to clean the interface between the twolayers of Al₂O₃ and reset the surface, a different O₂ plasma unit wasused to treat the surface with a lower power O₂ plasma (when comparedinventive example I10) to clean the interface. Inventive example I12 wasanalyzed as described in inventive example I10. The results of thenumber of peaks counted and average percent change in the ToF SIMS canbe found in Table 5.

TABLE 5 C3 I10 I11 I12 % % % % Analysis # Inten. # Inten. # Inten. #Inten. Polarity Species Peaks change Peaks change Peaks change Peakschange Positive AlF 0 n/a 3 10841 3 1334 3 1548 Positive B 0 n/a 3 35003 80196  3 23987  Positive AlOH 0 n/a 3 60 0 n/a 0 n/a Positive Si 0 n/a3 790 3 1714 3 1547 Negative AlO₂ 3 57 0 n/a 0 n/a Negative F 3 5926 31408 3 1337 Negative CN 3 225 3  858 3 1130

As can be seen from FIG. 30 and Table 5, the interface between inorganicdielectric material layers of the same material can be easily detectedby standard analytical techniques. The ToF SIMS data clearly shows thatdielectric multilayer stacks of the present invention can have specieswith an intensity change of 50% or greater at an interface when comparedto the intensity that is detected in a bulk film. Many species arepotential markers for treatment at the interface; although the interfacesignature is different for different samples and techniques the presenceof an intensity change of 50% or greater in one or more species iscommon between inventive examples I10, I11 and I12. Additionally,without constraining the magnitude of the signal change, one can seethat the simple presence of peaks within the intensity trace as afunction of depth is indicative of the presence of treatment at amaterial interface.

TFT Experiments to Probe Dielectric Quality

In order to further probe the impact of the dielectric layer quality andto evaluate the importance of the dielectric semiconductor interfaceTFTs were built according to the process flow illustrated in FIGS.15-27.

FIG. 15 a is a cross-sectional diagram the first processing Step of oneembodiment of a TFT 500 of the present invention, taken along the lineA-A′ of the plan view shown in FIG. 15 b. As shown, a substrate 510 isprovided having prepatterned gate 520. In the Example TFTs of thepresent invention the gate 520 was provided using the combination of SADand ALD, providing a gate having 1000 A of AZO as the conductivematerial stack.

A first patterned deposition inhibiting material layer 810 is alsoprovided on substrate 510 as shown in FIGS. 15 a and 15 b, and containsregions 820 where the deposition inhibiting material layer is notpresent. In the Examples contained herein the first patterned depositioninhibiting material layer 810 was applied using a Fuji Dimatix 2500piezo-inkjet printer. The inhibitor ink was a 2 wt % solution of PVPk-30 in diacetone alcohol. The pattern of the first patterned depositioninhibiting material layer 810 provides a via to the pad of the TFT gate520.

Next, as shown in FIGS. 16 a and 16 b, a patterned first inorganic thinfilm dielectric layer 530 is obtained by selectively depositing aninorganic dielectric material the region 820 of the substrate where thefirst deposition inhibiting material layer is not present using anatomic layer deposition process. The patterned first inorganic thin filmdielectric layer 530 covers the gate 520 of the TFT, and can be of anypattern that has this feature. In the present examples, a giventhickness of Al₂O₃ was deposited at 200° C., using the conditions listedfor Al₂O₃ in Table 1. Following the selective deposition of thepatterned first inorganic thin film dielectric layer 530, the firstpatterned deposition inhibiting material layer 810 is removed bysimultaneously treating the first deposition inhibiting material layer810 and the first inorganic thin film dielectric material layer 530. Theresultant structure of the simultaneous treatment is shown in FIGS. 17 aand 17 b. This treatment is preferably an O₂ plasma, and the examplesTFTs of the present invention were subjected to a 2 minute O₂ plasma at100 W and 0.3 Torr.

For inventive examples containing a multilayer dielectric stack, asecond patterned deposition inhibiting material layer 830 is provided onsubstrate 510 as shown in FIGS. 18 a and 18 b. Preferably, the secondpatterned deposition inhibiting material layer 830 is provided using thesame method as the first patterned deposition inhibiting material layer810, and has the same pattern as the first patterned depositioninhibiting layer 810. All patterned deposition inhibiting materiallayers of following examples were applied using a Fuji Dimatix 2500piezo-inkjet printer and an inhibitor ink was a 2 wt % solution of PVPk-30 in diacetone alcohol as the inhibitor ink.

Next, as shown in FIGS. 19 a and 19 b, a patterned second inorganic thinfilm dielectric layer 540 is obtained by selectively depositing aninorganic dielectric material the region 840 of the substrate where thesecond deposition inhibiting material layer is not present using anatomic layer deposition process. The second patterned inorganic thinfilm dielectric layer 540 as shown preferably has the same pattern asthe first patterned inorganic thin film dielectric layer 530. Patternedinorganic thin film dielectric stack 550 as shown is made up ofpatterned first inorganic thin film dielectric material layer 530 andpatterned second inorganic thin film dielectric material layer 540. Inthe present examples, a given thickness of Al₂O₃ was deposited at 200°C., using the conditions listed for Al₂O₃ in Table 1 for patternedsecond inorganic thin film dielectric layer 540. Following the selectivedeposition of the second patterned inorganic thin film dielectric layer540, the second patterned deposition inhibiting material layer 830 isremoved by simultaneously treating the second deposition inhibitingmaterial layer 830 and the second inorganic thin film dielectricmaterial layer 540. The resultant structure of the simultaneoustreatment is shown in FIGS. 20 a and 20 b. This treatment is preferablyan O₂ plasma, and the examples TFTs of the present invention weresubjected to a 2 minute O₂ plasma at 100 W and 0.3 Torr. It should beunderstood that comparative TFT examples C4, C5 and C6 of the presentinvention, and inventive examples I11 and I13 containing a single layerdielectric, have only the first inorganic thin film dielectric materiallayer 530 in place of the patterned inorganic thin film dielectric stack550. In these examples, the steps described in relationship to FIGS. 18a-20 b were omitted.

Next, as shown in FIGS. 21 a and 21 b, a third patterned depositioninhibiting material layer 850 is provides on substrate 510 and containsregions 860 where the deposition inhibiting material layer is notpresent. Preferably, the third patterned deposition inhibiting materiallayer 850 is provided using the same method as the first patterneddeposition inhibiting material layer 810. As discussed previously, allpatterned deposition inhibiting material layers of the Examples wereapplied using a Fuji Dimatix 2500 piezo-inkjet printer and a 2 wt %solution of PVP k-30 in diacetone alcohol as the inhibitor ink.

Next, for inventive examples I11 through I15 and comparative example C6,a buffer layer was deposited via selective area deposition as shown inFIGS. 22 a and 22 b. As shown in FIGS. 22 a and 22 b a patterned thirdinorganic thin film dielectric layer 560, also referred to as a bufferlayer, is obtained by selectively depositing an inorganic dielectricmaterial in the region 860 of the substrate where the third depositioninhibiting material layer is not present using an atomic layerdeposition process. In the present Examples, 250 Å of Al₂O₃ wasdeposited at 200° C., using the conditions listed for Al₂O₃ in Table 1for patterned third inorganic thin film dielectric layer 560. As shown,the third patterned inorganic thin film dielectric layer 560 has a thirdpattern that is located within an area defined by at least one of thefirst and second patterns of the first 530 and second 540 inorganic thinfilm dielectric material layers. For comparative examples C3 and C4 thisStep was omitted.

In TFTs that are formed by the combination of SAD and ALD, special careshould be taken to insure that when changing between the dielectricpattern and the semiconductor pattern that the interface is notdisturbed by the removal of the deposition inhibiting material. To thisend, for inventive examples I11, I12, I15 and I16, a patternsemiconductor layer 570 was deposited via selective area deposition asshown in FIGS. 23 a and 23 b. As shown in FIGS. 23 a and 23 b thepattern semiconductor layer 570, is obtained by selectively depositingan inorganic semiconductor material the region 860 of the substratewhere the third deposition inhibiting material layer is not presentusing an atomic layer deposition process. In the present Examples,nitrogen doped zinc oxide (ZnO:N) was deposited as the semiconductorlayer at 200° C., using the conditions listed for ZnO:N in Table 1. Asshown, the patterned semiconductor layer 570 has the same pattern as thepatterned third inorganic thin film dielectric layer 850 and was alsoselectively deposited using the third patterned deposition inhibitingmaterial layer 850. For comparative example C6 and inventive exampleI13, the patterned deposition inhibitor material 850 was removed with anO₂ plasma and then reapplied prior to selectively depositing thepatterned semiconductor layer 570.

Following the selective deposition of the patterned semiconductor layer570, the third patterned deposition inhibiting material layer 850 isremoved by treating the substrate with an O₂ plasma. The Example TFTs ofthe present invention were subjected to a 2 minute O₂ plasma at 100 Wand 0.3 Torr. The resultant structure is shown in FIGS. 24 a and 24 b.

Next, as shown in FIGS. 25 a and 25 b, a fourth patterned depositioninhibiting material layer 870 is provided on substrate 510 and containsregions 880 where the deposition inhibiting material layer is notpresent. Preferably, the fourth patterned deposition inhibiting materiallayer 870 is provided using the same method as the first patterneddeposition inhibiting material layer 810. As discussed previously, allpatterned deposition inhibiting material layers of the Examples wereapplied using a Fuji Dimatix 2500 piezo-inkjet printer and a 2 wt %solution of PVP k-30 in diacetone alcohol as the inhibitor ink.

Next, all Examples had the source/drain 580 formed on the substrate 510by the selective area deposition of a second electrically conductivelayer stack. As shown in FIGS. 26 a and 26 b, the source/drain 580 isobtained by selectively depositing a conductive inorganic material inthe region 880 of the substrate where the fourth deposition inhibitingmaterial layer is not present using an atomic layer deposition process.In the present Examples, 1000 Å of AZO was deposited at 200° C., usingthe conditions listed for AZO in Table 1 as the source/drain 580. Forthe Examples of the present invention, the fourth patterned depositioninhibiting material layer 870 was not removed prior to testing thedevice. FIGS. 27 a and 27 b are illustrative of a TFT after the removalof the fourth patterned deposition inhibiting material layer 870, andare essentially same as FIGS. 11 a and 11 b and should be understoodfrom the previous descriptions.

The Example TFTs were fabricated using the method described above inrelationship to FIGS. 15 a through 27 b. The relative differencesbetween the samples are called out in the following descriptions forclarity. In all Examples, 133 transistors were tested. Each transistorhad a characteristic channel width and length of 70 microns and 400microns respectively. Electrical testing of the transistors wasaccomplished by using a probe station to contact the AZO gate andsource/drain. The transistors were swept in the linear regime, with thedrain being held constant at 0.2V (Vd=0.2), and the gate voltage wasswept from −10 V to 20 V. The mobility (Mob.), threshold voltage (Vth),on-off ratio of the drain current (Ion/Ioff), the average gate leakagecurrent at the maximum gate voltage applied (Ig(Vgmax)), and the % yieldwere all evaluated for the Examples below and reported in Tables 5 and6.

Comparative Example C4

TFT with Single Layer Dielectric and No Buffer Layer on a GlassSubstrate

Comparative example C4, was prepared generally as described above.However, comparative example C4 has a single layer inorganic dielectricmaterial layer that is 750 Å thick that was obtained experimentally in asingle coating event at 200° C., using the conditions listed for Al₂O₃in Table 1 and 1740 ALD cycles each with a 100 ms residence time on theAtmospheric ALD equipment described above. Additionally, comparativeexample C4 does not contain a buffer layer. The sample was analyzed byusing a probe station to contact the AZO gate and source/drain, and theresults of this testing can be found in Table 6.

Inventive Example I13

TFT with Single Layer Dielectric and Buffer Layer on a Glass Substrate

Inventive example I13, was prepared as comparative example C4 with thefollowing exception. Instead of depositing 750 Å of Al₂O₃ in a singlecoating event, the dielectric layer was divided into two layers.Experimentally, after printing the inhibitor dielectric pattern, 500 Åof Al₂O₃ was deposited at 200° C., using the conditions listed for Al₂O₃in Table 1 and 1164 ALD cycles each with a 100 ms residence time on theAtmospheric ALD equipment described above. Next the sample was subjectedto a 2 minute O₂ plasma treatment to remove the inhibitor and clean theinterface between the two layers of Al₂O₃. Next, the semiconductorinhibitor pattern was printed and 250 Å of Al₂O₃ was deposited at 200°C., using the conditions listed for Al₂O₃ in Table 1 and 582 ALD cycleseach with a 100 ms residence time on the Atmospheric ALD equipmentdescribed above. The sample was removed from the Atmospheric ALDequipment to facilitate the switch to ZnO deposition. The sample wasthen reloaded into the equipment without any surface modification and300 Å of N-doped ZnO was deposited at 200° C., using the conditionslisted for ZnO:N in Table 1 and 30 ALD cycles each with a 50 msresidence time. The sample was then completed as comparative example C4and analyzed. The results of this testing can be found in Table 6.

Inventive Example I14

TFT with Double Layer Dielectric and Buffer Layer on a Glass Substrate

Inventive example I14, was prepared as comparative example C4 with thefollowing exceptions. Instead of depositing 750 Å of Al₂O₃ in a singlecoating event, the dielectric layer was divided into two layers asdescribed in relationship to FIGS. 15 a through 20 b. Experimentally,after printing the inhibitor dielectric pattern, 250 Å of Al₂O₃ wasdeposited at 200° C., using the conditions listed for Al₂O₃ in Table 1and 582 ALD cycles each with a 100 ms residence time on the AtmosphericALD equipment described above. Next the sample was subjected to a 2minute O₂ plasma treatment to remove the inhibitor and clean theinterface between the two layers of Al₂O₃. Next, the inhibitordielectric pattern was printed again and 250 Å of Al₂O₃ using the sameconditions as the first dielectric layer. Next the sample was subjectedto a 2 minute O₂ plasma treatment to remove the inhibitor and clean theinterface. Next, the semiconductor inhibitor pattern was printed and 250Å of Al₂O₃ was deposited at 200° C., using the using the same conditionsas the first dielectric layer. The sample was then removed from theAtmospheric ALD equipment to facilitate the switch to ZnO deposition.The sample was then reloaded into the equipment without any surfacemodification and 300 Å of N-doped ZnO was deposited at 200° C., usingthe conditions listed for ZnO:N in Table 1 and 30 ALD cycles each with a50 ms residence time. The sample was then completed as comparativeexample C4 and analyzed. The results of this testing can be found inTable 6.

TABLE 6 Buffer Layer Dielectric Dielectric Ave Std Ave Ave Av Sample (Å)(Å) Mob Mob Vth Std Vth Ion/Ioff Ig(Vgmax) % Yield C4 750 0 2.77 2.4110.66 1.80 4.09E+04 6.3E−11 34 I13 500 250 10.19 0.39 9.74 0.20 4.82E+051.5E−10 58 I14 250 + 250 250 11.43 0.42 9.43 0.16 5.29E+05 1.5E−10 84

As can be seen in Table 6, inventive samples I13 and I14 havesignificantly higher average mobility values than the comparativeexample C4. This higher mobility can be attributed to the care taken atthe interface of the semiconductor and dielectric. In these Examples,the semiconductor and third dielectric layer (buffer layer) werepatterned using the same patterned director inhibitor materialalleviating the need to clean the sample surface prior to the depositionof the semiconductor. Inventive example I14 also exhibits asignificantly higher yield than C4. This can be attributed to therobustness of the multilayer dielectric stack.

Comparative Example C5

TFT with Single Layer Dielectric and No Buffer Layer on a GlassSubstrate

Comparative example C5, was prepared as comparative example C4. Thesample was analyzed by using a probe station to contact the AZO gate andsource/drain, and the results of this testing can be found in Table 7.

Inventive Example I15

TFT with Single Layer Dielectric and Buffer Layer on a Glass Substrate

Inventive example I15, was prepared as inventive example I13. The samplewas then completed as comparative example C4 and analyzed. The resultsof this testing can be found in Table 7.

Comparative Example C6

TFT with Single Layer Dielectric and Buffer Layer on a Glass Substrate

Comparative example C6, was prepared as inventive example 15 with thefollowing exceptions. After deposition the second dielectric layer (thebuffer layer), the sample was subjected to a 2 minute O₂ plasmatreatment to remove the inhibitor and clean the interface. Next, theinhibitor semiconductor pattern was printed again and 300 Å of N-dopedZnO was deposited at 200° C., using the conditions listed for ZnO:N inTable 1 and 30 ALD cycles each with a 50 ms residence time. The samplewas then completed as comparative example C4 and analyzed. The resultsof this testing can be found in Table 7.

Inventive Example I16

TFT with Double Layer Dielectric and Buffer Layer on a Glass Substrate

Inventive example I16, was prepared as inventive example I14. The samplewas then completed as comparative example C4 and analyzed. The resultsof this testing can be found in Table 7.

Inventive Example I17

TFT with Single Layer Dielectric and Buffer Layer on a Glass Substrate

Inventive example I16, was prepared as inventive example I16 with thefollowing exceptions. After deposition of the third dielectric layer(the buffer layer), the sample was subjected to a 2 minute O₂ plasmatreatment to remove the inhibitor and clean the interface. Next, theinhibitor semiconductor pattern was printed again and 300 Å of N-dopedZnO was deposited at 200° C., using the conditions listed for ZnO:N inTable 1 and 30 ALD cycles each with a 50 ms residence time. The samplewas then completed as comparative example C4 and analyzed. The resultsof this testing can be found in Table 7.

TABLE 7 Buffer Layer Dielectric Dielectric Ave Std Ave Std Ave Av Sample(Å) (Å) Mob Mob Vth Vth Ion/Ioff Ig(Vgmax) % Yield C5 750  0 3.15 3.4010.92 2.07 8.02E+04 2.3E−05 57 I15 500 250 10.46 1.87 8.88 0.87 5.35E+051.0E−04 34 C6 500  250* 3.25 3.70 10.94 2.07 8.14E+04 1.5E−05 36 I16250 + 250 250 11.04 0.35 9.53 0.10 5.11E+05 2.4E−10 99 I17 250 + 250 250* 2.59 0.54 10.95 0.50 5.94E+04 6.2E−10 100 *I15 and I16 received 2minute O₂ plasma after buffer layer deposition

As can be seen in Table 7, inventive samples I15 and I16 havesignificantly higher average mobility values than the comparativeexamples C4 and C6. This higher mobility can be attributed to the caretaken at the interface of the semiconductor and dielectric. In theseinventive examples (I15 and I16) the semiconductor and third dielectriclayer (buffer layer) were patterned using the same patterned directorinhibitor material alleviating the need to clean the sample surfaceprior to the deposition of the semiconductor. Inventive example I15 andcomparative example C6 are structurally the same. The deleterious impactof cleaning the dielectric surface prior to depositing the dielectriclayer can be seen by the lower mobility measured in C6. Inventiveexamples I16 and I17 exhibit significantly higher yield than C5 and C6.This can be attributed to the robustness of the multilayer dielectricstack.

Parts List

-   1 providing a substrate-   10 applying the deposition inhibitor material-   15 optionally patterning the deposition inhibitor material-   20 ALD-   22 ALD-   25 simultaneously treating-   30 treating the surface-   35 applying the deposition inhibitor material-   40 optionally patterning the deposition inhibitor material-   50 ALD-   52 ALD-   60 removing the deposition inhibitor material-   81 nitrogen gas flow-   82, 83, 84 gas bubbler-   85, 86 flow meter-   87, 88 flow meter-   89, 91, 94 flow meter-   90 air flow-   92 metal precursor flow-   93 oxidizer-containing flow-   95 nitrogen purge flow-   96 substrate support-   97 example substrate-   98 arrow-   99 gap-   100 delivery head-   105 output face-   110 exhaust channels-   200 substrate-   210 first patterned deposition inhibiting material layer-   215 region where the first deposition inhibiting material layer is    not present-   220 patterned first inorganic thin film dielectric material-   225 partially removed first patterned deposition inhibiting material    layer-   230 second patterned deposition inhibiting material layer-   235 region where the second deposition inhibiting material layer is    not present-   240 patterned second inorganic thin film dielectric material-   250 patterned inorganic thin film dielectric stack-   300 substrate-   310 patterned deposition inhibiting material layer-   315 region where the deposition inhibiting material layer is not    present-   320 patterned first inorganic thin film material-   330 patterned second inorganic thin film material-   350 inorganic multi-layered thin film structure-   400 substrate-   410 patterned first electrically conductive-   420 patterned second electrically conductive-   425 overlap region-   430 patterned first inorganic thin film dielectric material-   440 patterned second inorganic thin film dielectric material-   450 patterned inorganic thin film dielectric stack-   460 patterned first inorganic thin film dielectric material-   465 patterned first inorganic thin film dielectric material-   470 patterned second inorganic thin film dielectric material-   475 patterned second inorganic thin film dielectric material-   500 transistor-   505 transistor-   510 substrate-   520 gate-   530 patterned first inorganic thin film dielectric layer-   540 patterned second inorganic thin film dielectric layer-   550 patterned inorganic thin film dielectric stack-   560 patterned third inorganic thin film dielectric layer-   570 patterned semiconductor layer-   580 source/drain-   600 transistor-   610 substrate-   620 gate-   630 patterned first inorganic thin film dielectric layer-   660 patterned second inorganic thin film dielectric layer-   670 patterned semiconductor layer-   680 source/drain-   700 transistor-   710 substrate-   720 gate-   730 patterned first inorganic thin film dielectric layer-   740 patterned second inorganic thin film dielectric layer-   750 patterned inorganic thin film dielectric stack-   770 patterned semiconductor layer-   780 source/drain-   810 first patterned deposition inhibiting material layer-   820 region where the deposition inhibiting material layer is not    present-   830 second patterned deposition inhibiting material layer-   840 region where the deposition inhibiting material layer is not    present-   850 third patterned deposition inhibiting material layer-   860 region where the deposition inhibiting material layer is not    present-   870 fourth patterned deposition inhibiting material layer-   880 region where the deposition inhibiting material layer is not    present

The invention claimed is:
 1. A method of producing a patterned inorganicthin film dielectric stack comprising: providing a substrate; providinga first patterned deposition inhibiting material layer on the substrate;selectively depositing a first inorganic thin film dielectric materiallayer on a region of the substrate where the first deposition inhibitingmaterial layer is not present using an atomic layer deposition processwithin an atomic layer deposition (ALD) system; forming an interfaceregion on the first inorganic thin film dielectric layer prior toselectively depositing a second inorganic thin film dielectric materiallayer region on the first inorganic thin film dielectric layer bysimultaneously treating the first deposition inhibiting material layerand the first inorganic thin film dielectric material layer after thedeposition of the first inorganic thin film dielectric material layer byat least removing the substrate from the ALD system to a differentenvironmental condition than that experienced in the ALD system;providing a second patterned deposition inhibiting material layer on thesubstrate; and selectively depositing a second inorganic thin filmdielectric material layer on a region of the substrate where the seconddeposition inhibiting material layer is not present using an atomiclayer deposition process within the ALD system, the first inorganic thinfilm dielectric material layer and the second inorganic thin filmdielectric material layer forming a patterned inorganic thin filmdielectric stack, wherein the first inorganic thin film dielectricmaterial layer and the second inorganic thin film dielectric materiallayer have the same material composition.
 2. The method of claim 1,wherein providing at least one of the first patterned depositioninhibiting material layer on the substrate and the second patterneddeposition inhibiting material layer on the substrate includes using atleast one of an inkjet printing process, a flexographic printingprocess, a gravure printing process, and a photolithographic printingprocess.
 3. The method of claim 1, wherein the substrate includes aplurality of material layers.
 4. The method of claim 1, whereinsimultaneously treating the deposition inhibiting material layer and thefirst inorganic thin film dielectric material layer after its depositionincludes subjecting the first inorganic thin film dielectric materiallayer and the deposition inhibiting material layer to a plasma process.5. The method of claim 4, wherein subjecting the first inorganic thinfilm dielectric material layer and the deposition inhibiting materiallayer to a plasma process includes at least partially removing thedeposition inhibiting material layer.
 6. The method of claim 4, whereinthe plasma process in an oxygen plasma process.
 7. The method of claim1, wherein simultaneously treating the deposition inhibiting materiallayer and the first inorganic thin film dielectric material layer afterits deposition includes subjecting the first inorganic thin filmdielectric material layer and the deposition inhibiting material layerincludes subjecting the first inorganic thin film dielectric materiallayer and the deposition inhibiting material layer to an etchingprocess.
 8. The method of claim 1, wherein simultaneously treating thedeposition inhibiting material layer and the first inorganic thin filmdielectric material layer after its deposition includes subjecting thefirst inorganic thin film dielectric material layer and the depositioninhibiting material layer to a wet cleaning process.
 9. The method ofclaim 1, wherein at least one of the first deposition inhibitingmaterial layer and the second patterned deposition inhibiting materiallayer includes one of a self assembled monolayer, a polymer, and a watersoluble polymer.
 10. The method of claim 1, wherein at least one of thefirst inorganic thin film dielectric material layer and the secondinorganic thin film dielectric material layer include one of a Al₂O₃,SiO₂, HfO, ZrO, TiO₂, Ta₂O₅, and Si_(x)N_(y) material.
 11. The method ofclaim 1, wherein the first deposition inhibiting material layer and thesecond patterned deposition inhibiting material layer have the samepattern.
 12. The method of claim 1, wherein providing the secondpatterned deposition inhibiting material layer on the substrate includesproviding the second patterned deposition inhibiting material layer onthe first patterned deposition inhibiting material layer after the firstdeposition inhibiting material layer has been treated.
 13. The method ofclaim 1, wherein the first inorganic thin film dielectric material layerand the second inorganic thin film dielectric material layer have thesame thickness.
 14. The method of claim 1, wherein forming the interfaceregion on the first inorganic thin film dielectric layer modifies achemical composition of at least a portion of an interface regionbetween the first and second inorganic thin film dielectric materiallayers.